Both will be fantastic! But in my opinion, I'd say grab the 40 if you intend to use it onsatge; being mic-ed up, or ran through a mixer etc. And the 20 for strictly home use, and recording etc. But, both are phenomenal amps, can be used in a variety of situations! 🤘🤘
I own a first verion ID Core stereo 40 amp which i bought uswd from my local Music-G0-Round a few years ago I get all the tones available in the later versions, lacking some of the later additional features. but can still connect to and use the arcetect software. the Starcaster Strat electric guitar By: Fender that I got the same place for around the same price and rebuilt/modded extremely sounds great through the amp. I plan to upgrade the amp with a pair of switched 1/4" extension speaker jacks to power a pair of 4X12" vertical/tower cabs I'll build for thqt purpose.when stod together side by side with the amp on top will be in essense a "Full Stack" the 40 wqatt amp shouls be able to drive the cabs well enough. and sound great doing it. the guitat with the hand made extended brushed stainless steel pick guard loaded with 3 quaD RAIL HUMBUCKERS WIRED LIKE A CLASSIC 50'S lES pAUL WITHp/p VOL. POTS FOR COIL SPLITTS AND THE BRIDGE TONE POT ALSO A p/p TO SCTIVATE THE BRIDGE AND NECK pICK-UPS TOGETHER REGASRDLESS OF THE 5-WAY SWITCH POSITION WILL GIVE IT NEARLY UNLIMITED TONAL VARIATIONS AVAILABLE THEN ADD ALL THAT ARE IN THE AMP . iWON'T EVEN TRY TO COUNG THE VARIETY OF TONES i CAN GET WITH ALL THOSE CONTROLS.