I have not noticed any difference between playing on Freeplay and playing with my own money. I often, just as Captain Bill mentioned play my Freeplay first and then play on (if there is a decent enough Video Poker game to play on).
What are you using your Freeplay on? If it's a Slot Machine that is not Video Poker, then it's more likely to offer a lower return than Video Poker does (although it also helps a lot to know how to play each hand of Video Poker in the best possible manner [which can be done even with the use of a printed out playing strategy chart]).
If you want to get the most of that money that is offered to you in Freeplay, if the Video Poker that is offered doesn't have a return of (at least mostly) any less than 99.1% in the Long Run, then you can be more likely to get a nice part of the Freeplay money out by playing (if it's available) Video Blackjack.
And do keep in mind that with Freeplay money, the second that the last cent of the Freeplay is played through, you can cash out whatever amount is left. So if you had $10 in Freeplay, the second that the $10 had been played through (for example this could be done by playing 8 hands of $1.25 per hand on a Quarter [$0.25] Video Poker machine), you can just cash that out and stop play entirely and walk out and take that voucher (or money) out and get paid and then you can leave the casino.
RecVPPlayer