I've tried a couple. In general they are all US products and therefore they are mostly setup for automatic downloading of transactions. UK banks don't seem to offer this, so you have to manually import, which I find a bit of a hassle tbh. They also usually have lots of features relating to US tax returns which gets in the way.
iBank 4
It's very detailed, categorising transactions seems simple. However, the import of data isn't hugely intuitive as you have to enter opening balances yourself and credit cards are fiddly as you have to get the transaction types correct or it double counts things.
I also have found that the reports have some bugs in where it has seemingly random amounts for some categories and I can't work out why.
i suspect that my problems are mainly due to me not using it correctly, so i'm persevering for the moment to see how it goes.
I haven't tried any of the budgeting features yet, but it looks comprehensive.
Money3
I tried this for about 10 minutes, but just couldn't get on with it, as things didn't set up very logically for account creation/data import.
I'm not really convinced one way or the other thus far. iBank seems to do what I want (track and categorise my spending) but has so many more features that its too complicated to use.
I think for me, building my own spreadsheet is probably still the best bet, though I may give ynab a try.