I'm the current lone Microsoft vote. I didn't, and still don't, always buy consoles at launch and tend to wait a bit. And even then most of them don't turn out extremely well because I still buy them early when there's not enough to really care about.
But the Xbox 360 really stands out for me. I bought it soon after launch on eBay because it was still nearly impossible to find in stores. It was bundled with four games and I think I picked up one or two others. I had a great time with its launch games, even the not-so-great ones (Kameo and Perfect Dark Zero come to mind). It had great online build in, which was something I actually took part in back then, and the achievements built in from the first day immediately got me hooked. I went through Condemned like three times in a row to get all 970(?) achievement points, Call of Duty 2 I played through on Veteran right from the start to get all those achievements, etc.
On top of all of that, it also had the Xbox Live Arcade popping out a game a week so I kept buying those cheaper games so my library grew quickly. The novelty of those arcade games and achievements made me buy and play a lot of rather shitty games but I was completely sold on all of it.
Conversely, some that I bought at launch that were underwhelming would be the GameCube, PS3, PS4, and Switch. I didn't get a PS2 or Xbox until nearly a year after the GameCube's launch and during that period I didn't play a single game for around six months because the GameCube had nothing. PS3 I got with Resistance and I pretended it was a really good game but stopped like 1/3 into it. PS4 was an adventure for me to get, got it with Black Flag, and put like two hours into it and then didn't really play the console much for a while. And Switch I bought near launch, eventually played around 10 hours of Zelda like nine months after launch, went through Mario Odysseey, and 10-20 hours of Smash Bros and traded it in after a year of owning it. I don't think I even unboxed my Switch for something like three months until my roommate wanted to try it out.