After playing on both now for over a month, I will say that they both have their positives and negitives.
888
If your like me and your a beginner with a small bankroll then 888 comes out on top with the better paying, more frequent and somewhat easier
freerolls. (Such as Lucky Chip, Royal Freeroll and Level+ Freerolls). There is some great and somewhat easy to win satellites if you want to play bigger tournements for great value. 888 also offers 4-man BLAST (Spin n Go) which are a bit tougher then the PS variety but sometimes offer prizes for more then just the winner. NL2 Cash Games and 6-Max SNAP (Zoom) seem really soft and great for a beginner to build a solid bankroll. You will also recieve promos for Free sports bets and casino freeplay which can also help you boost your bankroll.
Some negatives compared to Pokerstars are the smaller player base during off-peak hours. Less selection when it comes to choices of games. The software and lobby is a bit more cluttered then pokerstars.
Pokerstars
Pokerstars offered a great first deposit bonus with a ton of extra freeroll tickets from the pokerstars school. The software is top notch and there is always a lot of traffic to the site, which also means a lot of fishy players at the lower stakes. You can earn a lot of extras from the stars rewards program which will give you some extra value if your a high volume player. Great selection of different games including some you dont find elsewhere like UnFOLD and PowerUP style. Lots of tournaments for all buy-in levels, so there is something really for everyone.