Superb new formula to a classic series.
There are several characters that tag along during Adol and dogi's adventure, and due to story issues, a couple of them leave but are replaced by new characters that have all the acquired skills associated with the character that left. There are about a dozen skills for each character, and each skill can reach up to level 10 for maximum effectiveness. In all honesty, I believe Adol can literally take on this new adventure by himself, since my playthrough was on normal, I took the liberty to level up a bit of each and every skill for all characters; there's too many. Not that you won't be able to use them all, it is just that once you get the skills that require a bit more sp (skill points are the medium for mana in this game for you rpg vets), you find that the more expensive ones are more efficient to use.
Protip for new players, you do not need to have the skill make contact with the monsters, you just have to use them and they will gain skill experience that levels the skill up. Also, once you acquire the training accessories that help you level up your skills, it would be prudent to just use them for your entire playthrough, since all other accessories which boost hp, def, agi, etc, really are moot (since you would want dps), and leveling up negates those accessories.
As with each Ys game, the soundtrack is stellar. Dungeon's are complimented with music that simply puts you in a battle trance, and village bgm is quite soothing to hear.
Normal should be the de facto difficulty, since there is no incentive to play on any higher difficulty; other than increased boss hp and damage. The bosses are large and have a ton of hp, more so if you're playing on higher difficulties.
There's a multitude of weapons, armors, and accessories to find and collect. Ys seven just brings that old school item inventory to the series. I was amazed that even in the endgame, the most basic material from the beginning of the game (iron ore) was still used to synth high end weapons and gear, a nice touch to know that early game items are not worthless once you're in the final dungeon.
Time wise, it could take the player about 15-20 hours just to play through the main story, and an additional 5-8 more to complete the sidequests (there are miss-able quests which are gone forever on your current playthrough after a certain point) so make sure you use a faq to double check.
In conclusion, Ys seven is a superb Jrpg. It brings that old school ps2 feeling onto the PSP, and to accentuate a superb game, Ys seven's stellar soundtrack makes the gameplay even better; a must play for action Jrpg fans!