I believe it was Voltaire who, when asked who was smarter, man or
woman, answered, "Which man and which woman?" So, extrapolating
from Voltaire, your question begs further clarification.
I have--and regularly use--all 3: WinPoker, Frugal and
TomSki's "Stragegy Master" (SM). Each fills a useful niche in my VP
career.
For practice of the most popular games I prefer
Zamzow's "WinPoker". The graphics fill the screen better than
Frugal and I can set it up to automatically inform me (I use 200
hands--you can set it to whatever you want) how I'm doing.
Invaluable when learning a new game. Frugal does not have this
automatic feature, but gives me more ready-to-play games and a
stragegy card (WinPoker does not give you a strategy card). Altho
Frugal does give you a strategy card, I still use SM because one,
I'm used to it and two, (and this is going to sound stupid) TomSki
sounds Polish and being of Polish descent myself, ya gotta be loyal
to the 'bro'. I suspect that eventually I'll wean myself off SM and
avail myself of Frugal's strategies, but not right now.
If I could only have one, I guess I'd take Frugal because it gives
me two things useful in the casino. But because I can have more
than one, for home use I prefer WinPoker.
So, "which is better?" begs the question: Better for what?