Compact aside, the bigger ones have the same motor as the smaller ones, so bigger only means the convenience of not emptying it so often.
I'd pick for features :
Built in power tool socket for autostart would be handy with a mitre saw.
Bluetooth remote would be nice for anything else - I use a homemade remote all the time with my vac.
Variable speed is a good if you want to use it with sanders to stop it sucking down onto the work
And auto clean helps keep the suction up if you don't intend to buy filter bags :