I've got the JDK R22 and i really like using it on drums. It's definitely a great sounding unit that is solidly built. It's clean but it still has it's own vibe. It's a versatile comp that can work in stereo or dual mono, which is nice when you want to use it on 2 different mono sources like snare top and bottom. I rather like it on kick and snare actually and I will sometimes use it on mix bus and also while tracking vocals. It can't do heavy pumping action like an 1176 but that's why you have different types of comps for different flavors. I've used it on acoustic guitars a few times with great results too. The THRUST feature is awesome and i use it quite often. I would say its a great, inexpensive, first outboard compressor for general use, possibly the best in its price range per channel. Even if you have a wide range of outboard gear i still think this thing has it's place and will definitely get used regularly.
Attack and release times are a blend of program dependent and control adaptive but these are the values they vary from:
Attack times: 10-40ms
Release Times: 30-400ms
I've never really felt the need to have attack and release controls, if i need a more aggressive compression i just reach for something else anyways. Depending on how you set it, i think these times are well suited for drums. Mine is almost always strapped on drums.
Hope this help!