I have nothing but good things to say about the YJM pedal also! I found it to be such a versatile little beast it suits my variety of music. I play a lot of death metal stuff, and I use the YJM as a 'lead boost' type thing, I set my amp to a driven rhythmn tone, and use the YJM to cut through that if I want to solo.
It's also great as a sole source of overdrive, it can go from a warm fuzzy little tone, great for blues, through a nice rock tone, straight up to a screaming metal lead tone, and practically everything between.
At lower levels it's got an almost vintage tube quality, really sweet. I would say you could fit it into your gig bag regardless of the type of music you play, from blues, to jazz to funk to metal, it has a sound to suit anything, and no, I DONT work for DOD, hehehe
It's also pretty cheap too, so I would say it's very worthwhile to buy one and see what you think, you can always take it back!
Honestly, if you're looking for a great pedal, you can go FAR worse than this little monster

and about the tube screamer, I totally agree, everyone seems to use them, and from what I've heard, they're nothing utterly special, in my view there are dozens of pedals out there that do a better job, sound better and cost less!