If you'd asked this several years ago, id had said the WE, just based on price and available spare part/ upgrades. Having owned several of them, there was never any huge issues with the ones i had.
Now, however, id say the MWS platform. The DE versions seem a superb buy and parts are a lot more readily available for the MWS system. The reliability seems second to none and overall id say is the best option to get into GBB's (or if you own a gbb already and looking for other options)