Penny Arcade 3 is "fine" -- it's unique and solidly done, but ultimately just gets bland quickly.
The good:
* The core RPG gameplay is solidly done, with some interesting add-on skills, appropriately silly weapons and skills, and a good variety of unique and funny monster types.
* Not too long -- you'll finish in 6-10 hours
* The graphics -- considering it's intentionally the old-skool 8-bit style, look great.
The not-so-good:
- Gameplay gets old -- there's just not that much variety, and you'll use some very simple strategies to crank through most of the monsters without much trouble.
- The humor is a little flat and tame for Penny Arcade -- if you like the over-the-top crude humor of the webcomic or the other PA games, this one will feel bland to you.
Overall, it's not bad. It just wasn't fun enough for me to keep on playing.