warrior is 4 stroke so it's not picky
but yes the banshees are picky, well you can maybe maintain them less, but you'll pay the price of it breaking.
You have to clean your air filter in gaz almost every ride depending on dirt, then spray it. You have to chgeck your chain and oil it every time, you have to pre mix your gaz (which costs more than a 4 stroke... 20$ gaz and 6$ oil for a 20L can)
Then you have all the little things like changing your jets. On a motocross you change the jets in 3 seconds, on a banshee you need to unplug your carburators, then unscrew the cap over the floater (then gas spills) then change the jet and put back everything together. Usually when it's top shape you change your jet twice a year (summer/winter).
Oh if you have a stock or mildly modified banshee it should be not that trouble. If you start changing lots of things it comes more picky. You could get a stock one with maybe boost bottles and pipes/exhaust and shouldn't get too much problem. You still need to clean filter and oil chain often.
Etienne