Poker Office vs. Poker Tracker

[Snafu'd]

I did a search on the above subject line and did not find exactly what I was looking for, so if there is a thread that explains the advantages and disadvantages of the programs, I'd greatly appreciate the link. Anyway, I picked up Poker Office for free (well sort of) through an Empire promotion. Now they have released Poker Office 2. While some of the upgrades look cool, I am worried that there will be a PO3, PO4, PO140 that they are going to want to charge to upgrade to every time. I am curious if Poker Tracker does the same thing. I realize that PT is recognized by most users of this forum to be the elite software of its kind, so I'm wondering if I should ditch Poker Office and just go for Poker Tracker. Any comments on the two would be greatly appreciated. Thanks in advance.