Keep in mind, Mac said he only used the GM soundbank. This is the main problem with GM. It's convienient, but you pay for that in mediocre sound especially the drums. GM is restrictive. The GM standard only allows for certain things or the sound is not GM certified or whatever they call it.
Take the GM Rhodes electric piano patch for example. The GM soundbank only has one. Check out any other big name keyboard from Korg, Roland, Kurzweil whatever, they have like 20 different Rhodes. Is only one of them the best? No, there are many different kinds of recorded Rhodes that you've heard on records over the years just like there's all kinds of different sounding Strats. It's all in how it's set up and what sound you're looking for.
It's in all the other non-GM soundbanks that the Ketron as well as most any other synth on the planet really shines. The other drum kits in the SD2 are very good but the GM bank only allows for a few. The problem again is convenience. To get those great sounds, you have to take the time to pick each instrument per track rather than just let Biab use the GM bank. Everything's a tradeoff. If you don't have time to pick out the best sounds from the higher banks, then you can't complain about a so-so sounding GM bank.

Bob

Biab/RB latest build, Win 11 Pro, Ryzen 5 5600 G, 512 Gig SSD, 16 Gigs Ram, Steinberg UR22 MkII, Roland Sonic Cell, Kurzweil PC3, Hammond SK1, Korg PA3XPro, Garritan JABB, Hypercanvas, Sampletank 3, more.