Yes, I have played this before, about a year or so back, and it's a lot of fun. In fact, some friends and I are also thinking of starting up a game of this over the summer again.
I enjoyed it as a whole, however there are a few quirks that you might want to be aware of (I haven't kept up to date with recent versions, so some of this may not apply as much):
*First off, we found that the game works a lot better for small party sizes (about 3 max is what I would recommend). Our GM ran a game where there were 5-6 of us, and there were too many times where one or two players would have the spotlight (i.e., challenging a gym leader) and the rest of the party was stuck doing nothing until they finished.
*Our GM also made the mistake of allowing the party to purchase high-end TMs early on in the campaign (such as Thunderbolt). When our group was presented this opportunity, there was one of us who was too broke to afford any of these, so he was stuck with less powerful moves. These TM moves were way broken (at least for low level, we never made it to higher levels so I can't say if they are still broken or not there), so our GM had to give our opponents these moves as well to present a challenge to us. This made it hard for our friend without these moves, as he was now at a severe disadvantage.
*This is somewhat related to the above statement, but it is VERY easy for some players in the party to advance much quicker than others in trainer level, especially if the party ever splits up or has different goals in the campaign. Our party split up frequently, especially because of me since I had a poor Wisdom stat, and I had the habit of spontaneously rolling a Wisdom check, and I would wander off in a random direction (which led to many interesting discoveries and a very angry Pupitar that I caught but was unable to use/control, lol). This led to players adding new Pokemon seen to their Pokedex at different rates, some players missing opportunities to challenge gym leaders, etc., leading to players leveling up at different rates.
Despite the few flaws we had found with the game, I agree it is very fun to play (I'm typically not the type of person who can get into tabletop games like D&D very well, but this game was an exception and was excited to play it). I've also been throwing around the idea of possibly running a forum-based Pokemon roleplay using this system, since it'd be easier for more players to get involved since everyone would be posting at their own pace. If I ever do get one running (probably sometime this month if I do), I'd be happy to invite anyone here who would be interested in playing.