I use one with biab. Holds mash temp like a champ for small batches 1-2 gals. For bigger batches I put the burner on super low to help it maintain temp more precisely.
It's easy to take apart and clean, so you could probly use without a bag I guess
It's also ideal for whirlpooling, as the impeller is always going and circulating the wort, even when it's not heating. So I plop it back in after flameout, set the temp to 160 and it circulates wort as it cools from boil/212F down to my set temp.
Sometimes my bag will get caught in the impeller intake, so I just put my spoon in front of it. But the design wouldn't allow for it to rip your bag or anything like that. And it sounds an alarm and shuts down, so you'll know if it happens.
