Here's what I'd suggest, if you have the time. Go ahead and drop $25 on zen, then grind the rest of the 2500 zen via dilithium. Prices are cheap on the DilExchange these days, you'll have it in a reasonable amount of time. That's what I did to get my Odyssey and Vesta bundles.
I have the bundle and the 3 set bonus is not all that great beacuse it takes up too many console slots that you need to use for other things. But the Vesta is a wonderful ship. There is a ship for each carrier class. pick the one that suits you and just buy one vesta. I like the Tac vesta the best with the phaser lance. And be sure to upgrade the hanger pets to the Purple ones that cost Dil. If you are a SCI captin you can finally do some DSP and dish out some damage with this ship. Just look at the 3 ships and decide what you goal is. Tanking, Corwd Control, Healer, or DSP and pick one. The 3 set is nice but not worth 5000 ZEN. I bought it and ended up not useing the other 2 ships and not running the 3 consoles.
The Armitage is an Escort with the torpedo point defense and a hangar. The Vesta is a Science Vessel with numerous consoles and a hangar. Like the Odyssey, the Vesta works better when you purchase all 3. So you get 3 ships for the price of 2. If you think the Vesta looks cool and has a good setup, then go for it. Just do all the research you can by reading the blog, watching review videos of it on youtube, and asking opinions on it, but it ultimately comes down to your own opinion of if you like it or not.
Absolutely worth it. Loading out with all three consoles makes it especially powerful. It's only weakness is hull strength, but it's a science based light cruiser with decent turn rate and the ability to load heavy dual cannons, making it a counterpart to the Klingon raider.