EQ2 is very different from EQ in a lot of ways giving it a totally different feel from the old game.
Some classes sound the same, but when you actually play them they are nothing like their EQ counterparts. Combat is much more intensive, and moved away from the whole "hit auto-attack and sit back" mentailty that cames later on in EQ.
I personally play healer classes for the most part and have found that unlike EQ, you do not have to be a cleric to be a good healer. Druids and Shamen are excellent healers also, and as all 3 have different types of healing spells I can play them all without getting bored.
As for Vanguard - I played right through beta and found myself very bored with that game. Admittedly it was beta so bugs occurred but even so right before release it was still not my idea of a fun game.
Many of my friends liked VG, but all the things they said about it that they liked were things that you find in EQ2 - but as WoW players they didn't know this.
If you are going to play an EQ2 trial then as mentioned above, the "Play the Fae" is a great way to see the newest expansion before you commit to buying the game.
If you then decide that you want to play buy the Echoes of Faydwer retail pack (not the digital download) as that way you get the full game plus all expansions.
I hope you enjoy the game and if you have any more questions please come back and see us and we'll do our best to help.