Both classes are very intresting, both of them have their pros and cons but they both work in a completely diffrent manner.
I'll try to list the pros and cons of each proff. through my point of view, and I'd appreciate if you'd help me choose which one suits me better.
Paragons:
Pros:
- High armor
- Ranged
- Supports with various chants (something I find very nice)
Cons:
- Very limited number of attacks (as far as I saw), seems like a auto attack and buff spammer. I like the idea of spamming chants, but I really can't stand auto attacking class.
- Weak? Unwanted?
Dervish:
Pros:
- Cool clothings and weapons
- Avatars look nice
Cons:
- Melee
- Looks very messy with all of those enchantments, and almost every skill seems to remove one
- Damage output?
Those are some points, but the most important thing is which one do you think is more enjoyable? Both leveling and progressing wise. Will I enjoy playing a Paragon? Is it fun, or will I be a nothing more than a backseat healing monk-ey? Same question applies to the Dervish, will it be a messy uneventful class or will I have some action?
I value fun and overall enjoyment as very important.

I appreciate your opinions. =)