I have had 6 of these in two groups of three lining up my front walkway since 2005. Here are the conditions under which they are grown:

-In Québec City, Qc, Canada, zone 4. Long, cold, humid and snowy winters; hot and humid summers
-No winter protection whatsoever; they're usually covered in snow from late december to mid-march; usually with no more than three feet of snow and with one side quite exposed.
-Grown in full sun, in a well-drained soil that has been well-furnished with compost but without other fertilizers.
-No pesticides of any type
-Some physical damage every year due to snow removal.
-No pruning

My results:

-Some winter damage at the tips but it's rather minor. It's quickly covered up by new growth anyway; I've never had to prune them for this reason.
-Blooms from late june to late july/early august. A striking display to say the least. flowers are large and abundant. Few hips. Fragrance is light but pleasant.
-A lot of aphids on shoot tips and buds during some years but no real damage. Susceptible to caterpillar damage but not as much as many other varieties; I've never had it badly defoliated.
-No disease of any kind were ever observed.
-Grafted; first sucker was seen 3 years after planting; one more the following year (now). I expect it to eventually sucker more.
-Planted 3 in a line 9 feet long. Plants filled up well and make a uniform low hedge about 30 inches high by 30 inches wide.

All in all, one of my most loved plants in my garden. Though I normally favour rebloomers and roses with a strong fragrance, the show that this variety gives is so amazing that it's more than forgiven for blooming only 6 weeks and having only a faint fragrance. Its winter hardiness and overall health and form are icing on the cake. A must-have.

UPDATE - JUNE 2010

Last summer, all six plants were basically razed to the ground and trampled on for three weeks in late june for work on the outside on the house. At the end of the season, I had abundant, albeit short, growth on all six plants, averaging 6 inches in height. This summer, it's as if none of this had ever happened; the plants are flowering as usual and overall growth is excellent. The worst that I could say is that the plants are - maybe - a few inches shorter than usual. Only 4 suckers since planting so far, counting the two mentioned earlier.

Also note that we have had a very unusual winter this year and I expected some damage. Snow cover was very thin and disappeared altogether very early; the plants vere exposed to several serious frosts (-15 C to -20 C) long after snowmelt.

Again, a very hardy and vigorous plant; I still heartily recommend it.

UPDATE - MAY 2016

I have sold the house where these have been planted but I frequently drive or walk by it. The owners are clearly letting my flowerbeds go wild. Gallica Versicolor is definitely winning over the front of the house and the original six plants now cover an area about 9 feet by 9 feet. And they're still spreading... So, again, a very hardy plant, suckering can be a problem but is manageable if you take the rogues out every year.

I've had a dozen plants of this variety as a hedge since 2003 under the following conditions:

-In Québec City, which means zone 4 with damp, hot summers and cold, humid and snowy winters
-On a windy street corner, facing south, about 8 feet from traffic, with decent sun during midday only. Parts of the hedge are quite shaded.
-No pesticide or fertilizers of any sort
-No pruning except for dead wood in the spring
-No winter protection whatsoever; snow cover usually between 2 to 4 feet

Here are my observations:

-A complete lack of pests of any sort to this date, even when some other roses are being chewed up by caterpillars, covered in aphids or defoliated by black spot. Mildew is not common in my garden so no comment on this specific disease. So it's great for a no-spray situation. And when I say "complete", I mean it.
-Very floriferous, apparently unaffected by the amount of winter dieback. The more shaded plants do not bloom as well and are smaller but I still get a decent amount of flowers from them.
-Not very bushy, rather anarchic growth. Must be planted close together to yield a decent hedge. Mine were planted 2 and a half feet apart and I should have planted them closer. Not a first choice for hedges.
-The higher plants reach close to 7 feet each year, but single plants are not very uniform (i.e. a few canes from the same plant reach this height put the plant is still not very even). Growth seems unaffected by the previous winter.
-Blooms from late june to late august; very reliable. Few hips. The flowers have an almost fluorescent glow that is great for brightening dreary areas.
-Though grafted, they have had plenty of time to root over the rootstock. Not a single sucker as of 2009.
-Very prickly. Great for stopping intruders.
-Barely perceptible fragrance.

All in all, a very nice plant despite its uneven growth.

I've planted five of these in a flower bed under these conditions:

-Québec city, Qc, Canada, in zone 4 with hot, humid summers and cold, humid, snowy winters
-Full sun and average exposure to wind
-Planted in a well-drained, compost-rich soil with no supplemental fertilizer
-No winter protection whatsoever, except for about 3 feet of snow
-No pruning except for winter dieback or damaged canes
-No pesticides of any sort
-Planted with three feet apart from each other

Here are my results:

-Extremely vigorous plants. Yearly growth averaged 6 feet vertically; I've had one 10-foot high cane about an inch thick one time. 8-foot high canes were common. Canes are stiff and extremely thorny, one of the spiniest roses I've had.
-Laterally, the bushes have filled up nicely. Not uniform enough to make a formal hedge but enough to make a more natural-looking hedge
-I've had very little winter dieback; a few cane tips here and there and some physical damage. Come late spring, any damage was completely hidden if not pruned off.
-Foliage was dark, lush and great looking. Imagine a rugosa texture, but dark green with red accents. This alone would make it a great-looking plant even if it never bloomed.
-Very susceptible to black spot; my plants could be completely defoliated by the end of summer. I've also had some problems with caterpillars chewing them up. No sign of mildew, but I've never had any in my garden yet. I have taken them out of my garden after 4 years because of the black spot problem.
-Gorgeous, vibrant, large flowers produced in abundance from late june to late august in my garden. Combined with the plant's size, it makes for an attention-grabbing plant. I've never had any fragrance to speak of.
-Grafted and no visible suckers in 4 years. 2 years after taking them out, I have a small sucker left that I had apparently missed.
-Never needed any watering or extra attention.

All in all, a first-rate plant if black spot is not an issue in your area. I have not sprayed it since A) I try not to spray and B) having a rugosa-like foliage, I feared I would damage it by spraying. But if you're willing to spray, the whole black spot issue could become moot. If it were not for this problem, I would never have taken them out of my garden as they were some of my favourite roses. Just be sure to leave them some room to grow, these are definitely not delicate bushes.