As with everything else, the following is only a personal opinion, but I must say that even though I've been quite satisfied with Odyssey pack at first when it came out, now the more I play STO the more I despise standard cruisers for PvE in general...
It's all about DPS recently, assuming you're not playing PvP. People may argue that cruisers can in fact deal decent dmg, but beams and torps are never going to do the same thing several dual cannons and turrets with CRF/CSV can. In addition, cruisers are barely able to turn and as such the only role they're good for is tanking and team support.
The Odyssey variants are the most versatile cruisers in the game - I'll give them that. 10 console slots in different configurations as well as universal boff stations make them one of the best big guys FEDs have.
But you need to ask yourself if you want to fly a support cruiser in the first place. If yes - then by all means get Odyssey. If not, then wait for Vesta or some PROPER Federation Battlecruiser (i.e. one that's actually able to turn and has lt.cmdr. tac station - not like that garbage called dreadnought).
As for the variants, not much to say - pick tactical if you want to get the most of your energy weapons. Engi variant is only good if you're gonna really make use of the 5 engineering slots (i.e. tanking and defense). For every other purpose take the science variant, as it gets free sensor analysis that doesn't do that much, but is always a nice addition.
As for unique consoles, the only one I found useful was Chevron Separation, as it drastically increases your turn rate. The Aquarius escort is honestly useless, and worker bees heal way too slow.
If anything I can at least say that I'll be switching from Odyssey to Vesta on both my Sci and Engi toons the moment they appear in the C-Store. And I don't think I'll ever go back to flying this or any other standard cruiser in the game. I'm waiting for the Andorian Battlecruiser, hoping it's going to turn out similar to KDFs Fleet Vor'Cha, which is my new love on my KDF Engi toon.