Microgaming and Pacific are the softest I have ever seen.

I have sworn never to play on Microgaming again because I hate it with a violent and overwhelming passion, but if you can cope with rampant shortstacking and ratholing, low traffic at certain times (but not bad for Canadians I don't think) and variance on steroids then go for it. Their rewards are amazing - I made more than $1.6K in bonuses and rakerace in a month at one site playing just 30K hands of 50/100NL.

Pacific's software tilts the hell out of me, but for epic fishiness it can't be beat. I swear you can take a 5NL game to 50NL there and come out on top.

Never had any withdrawal issues at either of them.

I don't think iPoker is any softer than Stars. If anything the standard is higher. Upside of course is that there are always games going.