We did the walkway and french curbs in poured white concrete, and we love it. Our next door neighbor poured a patio in the back as well, and he loves it (also white). He built a lumber... hmmm, it's not really walls, it's like a framework of posts with just a few pieces of lattice here and there that he's growing grapes and flowering vines up, looks fantastic. We're going to copy his patio at the next house and use the same guy (who was fantastic, his whole crew). I don't have his card here at work but I wouldn't hesitate to recommend him in a heartbeat.
That said, down the street a bit a neighbor did the same thing with colored patterned concrete and it looks fabulous too, and she was extremely happy with the people who did it, and their website shows some really impressive stuff (although of course colored two/toned is way more expensive than plain white). I think it was
www.patternedconcrete.ca or .com or something like that, they're in Mississauga, and again, she recommends them highly.
Personally, I like concrete much better than interlock, but that's because I like low maintenance - no weeds growing in the cracks with concrete.