Bought my F-50 1x12 in 2003 from Esden Trading. For the price I paid ($1500) I think it's a great buy. I wanted a portable combo amp with great cleans that take drive pedals well, and it fits the bill. I've used it at home, in the studio and on small and large stages, it always performs. The cleans are unique - darkish, thick, slightly compressed, possibly a bit Fender-ish with the treble on higher settings, but without that sparkly brightness or shimmer. Notes bloom really nicely and many overdrive pedals tend to take on the amp's character. The drive channel's not for me, but it's ok for emulating that Dual Rectifier-ish distortion (albeit slightly tamer) in the studio.
As my main tone is derived from pedals through a clean amp, an amp's distortion is secondary. The only other Mesa I'd consider is the Lone Star 2x12 which has an amazing depth and rich cleans - the drive channel sounds wonderful too. The Express series sounded alright, I thought my F-50 still sounded better but then again I didn't AB it and it could be because of the NOS tubes I'm using. I think playing with the Express's Contour knob could yield some interesting tones.
If Mesas could be bought for prices comparable to US prices, then yes - they'd definitely be a good choiice. Well-built, roadworthy, powerful and there's different models to suit most players' wants.