I've always used Windows. I started with Windows, and I sure will end with it
I've always been a mix of 32-bit and 64-bit. My first Desktop was 32-bit and I had it for 3 years (well it was a shared family PC). Then it broke and I got a personal netbook which was awful, again 32-bit and I had it for 2 years. So that is 5 years of 32-bit, but, during those 5 years my dad got a 64-bit laptop which I used a lot and it's still running all these years later. Now I have a 64-bit laptop.
I have ran into compatibility problems with programs running 64-bit in the past. But not recently.
I've been using 64-bit for years now without any issue. I would say most computers sold today, if not all come with 64-bit systems. I work at Office Depot and that's all we sell in our computers.
I have used both over time, but the last 6 years has been 64bit.
Have used:
Windows xp 32 bit
Windows vista 32 & 64 bit
Windows 7 64 bit
Windows 8 & 8.1 64 bit