I used Vista from Beta 1 onwards through mid 2010. From RC (build 5700 iirc), I had very few problems. I do acknowledge I was an outlier, but the truth is that Vista was never all that bad. Most of the early problems were related to two factors: 1) bad drivers - the driver model changed significantly from NT 5.x to 6.0 (in particular graphics). Manufacturers dragged their feet adjusting to the new reality - partly out of laziness and partly because the Longhorn project took so long to complete. NVIDIA was particularly bad early on. Microsoft's own analysis showed 80% of crashes were related to graphics drivers. Eventually these were sorted out.
The other problem was the "Vista Capable" fiasco. Microsoft allowed manufacturers to put the Vista Capable sticker on computers with only 512 megabytes of RAM. Many of these had integrated graphics, which sucked more RAM meaning you didn't even have 512 to begin with. As someone who used Vista even on a 1GB system - I can't imagine the torture that would come to the human psyche attempting to run with only 512.
There was also the fiasco with the Intel i900/915 chipsets. Early on they were supposed to have "Vista Certified" support with full Aero - indeed they did through Vista RC1. At RTM that was eliminated and you were knocked down to Aero Basic because of the lack of a "hardware scheduler" (oops!).
As for Vista itself, most of the serious bugs (there weren't many - the biggest was some network inconsistencies and file copy issues) were resolved by SP1.
The main problem with Vista today is the immense amount of updates one must install - SP2 isn't cumulative so you have to go with SP1, then 2. Then there's a Platform Update which backports DirectX and several other things from Vista but Microsoft refuses to let you download in one combined hotfix outside of Windows Update. Microsoft also refuses to support current software on Vista anymore because "mainstream support" ended early in 2012. So no IE10+, no DirectX 11.1, etc.