It's only $25, it is slightly more efficent and if you play on Party it shows mucked hands without having to look thru the hand history.

For that reason I recently choose to buy it, otherwise GT+ was working fine for me.

The only thing I missed was that I could put GT+ in icon only mode, and just mouse over to see the actual stats. PokerAce just shows stats and if you click on a name you can see their actual rating. It's probally better with just the raw data anyway because it allows me to make a more intuitive decision on how to play my opponents.