Never really enjoyed using SBS mods too much,as my hands are too big, and most modders put the fire button very low on the front, where only my ring or pinky finger naturally fits, which combined with the small size, cramps my hands (already have nerve damage from guitar/ welding for 15 years)...

...but I totally get the appeal, and there are some nice designs coming out, occasionally.

My favorite? The Supbox, due to a bigger body and higher fire button, but I get the most use out of the Mixx with 21700, and this little gem...which afaik, is the only with a sliding, adjustable body that allows for different height rtas - something that should be integrated into mainstream SBS mods.