I original played this game back when it came out on PlayStation waaay back in 1998 and it was one of the best games I had ever played at the time. It even came out just 1 year right after another epic game (Final Fantasy 7). It is surprising to see the level of detail, quality and polish the developers were still able to put in this game.
There are many highlights to this game.. (in no real order)
Well Presented to Age of Marketed Audience (no kiddy jokes or too unrealistic characters... for the games theme anyway)
Character Jobs/Classes (Including 2 new jobs in the PSP version)
Varity of Items and Equipment (even more than the original)
High Level of Customization
Multiplayer (new to the PSP version and also new items only obtainable via multiplayer)
With all these great points its almost hard to come up with the down side to the game. A difficulty selection mode would be well appreciated here, but it doesn't really fit in with any other Final Fantasy game as they never had difficulty settings.
Enemy monster levels keep up with your character levels to try and keep battles difficult, however scripted battles with enemy humans do not level scale, so you may find yourself over-leveled compared to your opponents making it rather easy. This is really only an issue however if you tend to grind for JP and EXP by purposely running into random encounters on the map.
The other downside is that multiplayer is very unbalanced depending the person you are playing against. (levels, equipment, abilities, etc..)
It can be possible for 1 character to completely demolish a whole team if his/her level and equipment is better than the other person's.
Even with this problem there are still user-made solutions to help out..
My personal solution is to take an end game file, save a duplicate then proceed to deleting all special character, items, equipment.. then hire 5 new characters to play only online with a friend. (who will do the same thing).
Play online with each other exclusively with that file and don't buy anything in the shops, at the end of multiplayer battles, the winner gets 3 chests, and the loser 1 chest. Players can slowly accumulate equipment this way and every item can help turn the tide of battle. They also keep any JP (but gain no EXP) so your characters will always stay level 1 but you can still learn new abilities and unlock new jobs.
Or just make your own rules to get the most fun out of it. The real key is to this method is to find someone you know who you can play your party exclusively with.
There are so many possibilities in this great game.. It has been around for ages and even still people will find new ways to play the game and reinvent it. If you haven't played it you are certainly missing out.