mk2 doesn't feel as solid to me, always felt like there was no substance to it. Rust problems are the biggest issue. I heard that a much more efficient rust-proofing method/substance was created not long after the mk2 launch although the mk3 isn't great for anti-corrosion.
If you get a mk2 you need to KNOW what you're doing, because things break. Alot. Very rarely anything significant but sensors, pipes etc. things that deteriorate with age and if you need to take it to a garage every time it'll leave you out of pocket.
mk2 is more fun to drive though, I miss mine like mad but it was getting too much to run and repair. Glad my mk3 is gone now though, loved it but it didn't have the same head-turning effect that a mk2 has