I have a Gazelle Orange C7+ and I like it a lot. Very stable and a cushy, comfortable ride that makes anything else I've ridden feel a bit basic (to be fair, they were). Obviously it isn't a speed machine; you will get overtaken by a great many people but it bowls along happily enough on the flat to get you somewhere in good time and good order, plus you don't have to mess about having to change in and out of trousers that would get eaten by a chain.
You do notice the weight going uphill, but how much of a problem it is really depends on how steep and how long the hill is (I suppose that's stating the blinkin' obvious). I test rode a sportier Gazelle in Oxford which blatted up some short hills like they weren't there. On the one I actually bought I notice inclines straight away, but I don't actually mind that much because exercise was part of the point of cycle commuting in the first place. It goes up short, inclines like ramps without a problem, but you want to be moving at a fair clip first. On longer rides with child seat and occupant on the back I can do up to about 4% without difficulty, just slowly. Long, shallow climbs take it out of me the most, but then Smallest Boy and his seat do add another 20 kg.
Probably my only issue with it, if you can call it one, is that it is transport in itself rather than transportable. I would really like to take it further afield sometimes to ride some other places, but it's a step through and I would worry about that much weight on a false bar for a car carrier. Lifting it up onto a roof carrier would be a challenge and then some. I would need a walk-on carrier to do it, so any journeys begin at home. That has made me hanker for an n+1, something light that I can throw onto a carrier and go.
Finally, while typing this I got a phone call from the local cycle hub who were investigating a bit of chain slip which had just started. Some minor adjustments of the hub gear are costing me the princely sum of a tenner.
Based on my experience of the last six months I'd buy one again, but I'd still want a lighter bike as well for other days and longer journeys.