Okay everyone, I can see this topic is a fairly controversial one but I think it very much is one based each user's PC's & setups thereof.
To Exodus firstly-from a technical standpoint, I have experienced much of what you have stated. Despite a few tries of later versions of WinUAE, my regularly used version remains WinUAE 08.8r8. I too have tried later versions such as WinUAE 08.14x series & found them far too choppy sound/gfx wise compared to WinUAE 08.8r8.
I have also tried the early alpha of WinFellow but failed to get it loading up ADF's into a 16bit 800x600 or have sound either-I got all sorts of squashed letterboxed screens but thats it...
Although I can understand Exodus's frustration's re WinUAE it does seem like the heart of the problem(s), lie in each person's different system.
Owning a Celeron 266 myself(on Win98), I'm realistic-it's old & I shouldn't expect any future WinUAE's to run fast with all these extra features-even 08.14x series.
Whilst there are several "ports" of WinUAE out there the programmers are obviously designing versions with faster PC's in mind-hence those mentioning their Win2K or XP monsters are motoring along without problems.
Then there's the issue of emulating the later AGA chipsets & other such features too. In an ideal world, a programmer who'd won lotto with a lot of free time on their hands might ask the WinUAE guys for the source code of WinUAE 08.8r8 & do a largely complete version for people who just enjoy playing old A500/600 games for a speedy emulator on older PC's.
When someone just looks at the specs on paper of a machine designed in the mid-eighties & with an 8Mhz 68000 & a few custom chips & 4096 colours, it's easy to think that a 400Mhz PC with TNT or GEforce or something with millions of colours should handle it with ease.
But the reality is for the extra features above & beyond the original intention's (the "save state" feature for WinUAe), it sadly means they'll be developing for the Win2K/XP with improved features of those speedier OS's & machines to handle these additions.