cetra is the easiest to grasp, though some others save a lot more time overall with more micromanagement - if you can get a rope relic on boston it's easily much better than cetra, for example, cetra does have the weakpoint of no horizontal movement (which can really set you back if he gets knocked way down) and no way to defend from long-range stuff, which means he is a great support but needs someone else to help
the jump pad on gamma is also really good at turn optimization when you have a lot of friends, it just is a lot harder to grasp.
cetra is generally pretty strong, - honestly, we didn't get to do ANY balancing at all - all the enemies and buddies are as they were when they were first implemented more or less, we implement them and then we move onto the next thing. we only fixed fatal bugs afterwards, so other than that, we never touched cetra after he was made sometime in late day 2 or early day 3
really, we'd prefer all buddies to have support abilities that move other buddies, the fact that boston doesn't is a bit unfortunate (unless you are REALLY trying to save turns, in which case you can use bostons gun+ jumps to knock all of your other buddies back somewhere and save like 6-8 turns at best... but maybe you don't want to shoot your friends !! )
we will take all of this into consideration in the case we decide to flesh this concept out fully, thanks for playing :)