Get all of them : D
They all have there fun and unique things about them.
I'm trying to avoid doing that, being more on the Compulsive side of OCD leads to more dollars spent than is really desirable right now. More looking to acquire a sizable arsenal that would get me through any war barring any stock blaster war.
Arh fair enough, well for wars I guess it depends on the war and game modes really.
IMO personal taste on a non-OCD side of things the Stampede and Vulcan are very fun and can do some crazy mods to them.
Just a simple battery mod is fun with them. Range sucks with AR in but still fun.
Rayven, they are nice light gun but need a voltage upgrade for sure and a few other tweaks.
AT's are nice (Raider have a better priming feel IMO) but the 18 round drum is very nice to have.
It really depends on which way you want to go and personal taste.
What I would suggest is go for a look search on Google, Trool the mods section of this forum and and YouTube
Check out all the guns you plan to get and see how they can be modded.
All just suggestions but maybe that will help you decided what you want get next to suit you : )