Re: Windows 10 = Windows Vista
Vista is quite good (now). The very popular Windows 7 is closely related to Vista, and it hasn't held it back a bit.
Vista was perceived as bloated and slow when it came out. Some of this was because Microsoft gave in to Intel's demands that PCs using its 915 chipset be certified for Vista, even though they were really not up to the task. MS created the "Vista capable" moniker for them, which meant it would run Vista, but it wouldn't be optimal (the optimal experience got a 'puter the "Vista Ready" label).
As could be expected, people didn't know the difference, and they came to associate the poor performance of Vista on "capable" machines with Vista itself. In addition, the early drivers for Vista were far from optimized, and that just made everything that much slower.
The Aero interface, now one of the things that people are begging MS to bring back, was seen then as useless eye candy that contributed to the slowness and bloat of Vista. On a machine that had the chops to run Aero, it was great (and many users of such machines liked it), but lower-end or older PCs were simply not powerful enough (particularly in the graphics acceleration department).
Not all of the complaints were without merit. In a series of well-publicized articles in computer magazines, Vista was beaten soundly by Windows XP in things like file copying-- even on the more powerful machines.
Over time, hardware caught up with Vista, and the drivers evolved to be faster and leaner, as did the OS itself. By the time 7 arrived, just about any new PC you could pick up at Best Buy would be able to run Aero without issue, and the complaints about Vista being slow and bloated began to fade. I really don't know if the file copy issues as such ever were resolved, or if the hardware just got speedy enough to make OS differences less important.
I'd much rather run Vista today than 10, though Vista's cut-off date is near. Vista had a rocky start, but it matured nicely as the problems that made it unpopular were solved over time.
Windows 10 is disliked for completely different reasons than Vista was. Win 10 is not slow and bloated-- by all accounts, it seems to be a bit faster than 7 on average (it was a little bit faster for me, but nothing to write home about). What ails 10 is intentional... the "features" baked into the OS are what people don't like. By contrast, Vista was never meant to be slow and bloated. Those were not core features... they were flaws that MS would have loved to get rid of (and for the most part, they did, in time). Vista wasn't crappy by design; 10 is.