They're offering a group buy over at IK ...I remember this plug as GREAT ...but the interface is really hard to work with...

That's the main reason I stopped using it.
 
I don't know if that has changed.

No change.  They "say" version 3 will be out this year.

I think I've heard that many times. 

It's also very wonky if used in 64-bit applications. I got it just to get on an upgrade path to the long awaited new version

Yeah, it's not the best, which is a shame because there are some very useable sounds, but I don't use it often as it's too fiddly. Resident IK guru (IK Obi) has recently said that v.3 is imminent, which could well be true, but.............well, it's been imminent for a looonnngg time now. I guess there will be upgrade deals for existing users, so if it's cheap enough, it may be worth having just to qualify for that.

Thanks for the answers folks!!
 

SampleTank has been causing me problems since I upgraded to Windows 7.  It now crashes Sonar a lot, so I have stopped using it.  I don't have a problem with the GUI though.
 

No stability problems here, but yeah, GUI is still too small - especially for older eyes (like mine).
 
That said, I still use it by opening on my second monitor with lower resolution (everything's a bit bigger).
 
The other thing that helps a lot is to change the look to lighter colors, so there's more contrast.  This is very easy to do - saturation knobs are on the front page.

Agreed, GUI is way too small. I have 'older eyes' also...
I only have one monitor.
I use Windows Magnifier to enlarge the text. 
PITA but it works after a fashion.