sci oddy is a great ship and so is the tac version. If you are looking for a cruiser with a more tactical layout the tac oddy is certainly the better choice, but only slightly. I would suggest however to use both ships with ltcmdr tac boff if you do PVE, stfs.
you can still fill the universal ensign with a sci or a engi.
personally i run this setup on a free oddy which is similar in BOFF layout. I'm doing pretty well dmg wise even with an engi captain. (well above 4k dps without buffs)
I could do more in a tac oddy or a sci oddy actually. I hear the aquarius support vessel is a waste, since you can't have it together with the saucer sep.
The tac Ody can be an excellent vessel.
Look at the Cruiser 3.0 thread in the PvP section for some really good builds designed by the PvP crowd that makes the most of the Ody and other Cruisers in game.
wondering if I should buy this ship i have been experimenting with escorts but I seem to be more comfortable with the bigger ships that I can take more damage any input will be great
The tactical Odyssey is a good, but SLOW, ship. Keep this in mind.
Don't get it for the Aquarius. There are a few people who swear by the Aquarius, but I call it the Barge of the Dead. In my experience, it has earned that nickname. If you want the best Odyssey console, then pick up the Ops version, as it has saucer separation, which is (IMO) far and away the best bonus, letting you change into a much quicker cruiser at the push of a button. Note that with the separation, you can get a bit of the best of both worlds - the separated Odyssey is still a decent battleship, with additional firepower (you can hit harder when separated).
However, there will be a hit to firepower overall for taking the ops Odyssey (as it is missing one tac console, and instead of +10 weapons power you get +5 weapons power). One thing to keep in mind is that there are limitations to the saucer sep, most notably cooldown and a loss of some durability while separated. You need to be comfortable with the slow nature of the ship no matter what version of the ship you pick, as at the end of the day it is what it is.
I personally would recommend that you consider picking up the pack - while expensive it offers maximum flexibility and your choice of the full three-piece Odyssey set.