The MONBOSH is going to feel alot like your Fleet Sovereign. (which is a great ship btw)
If you're really looking for a change of pace look towards a science ship or escort. You can buy a mirror ship cheaply and test it before deciding. Better to test than waste 100 million EC on something your not going to like.
Strangely enough I just went BACK to the Assault Cruiser from my Oddy and my Avenger Battlecruiser. It still does a lot of damage and tanks a lot of incoming fire. There's honestly nothing wrong with the ship.
If you just want to try some other ships out look for either of the 2 mirror escorts on the exchange. They're pretty cheap and only cost ECs. That'll give you a different playstyle without breaking the bank.
Other than that -- and this is just a personal suggestion -- might I suggest the temporal destroyer from the lobi store? Universal slots so you can customize it as you wish. Or for a very different playstyle, JHDC for some carrier play-style.