I'm currently using a Effectrode PC-2A and talk about a magic box! I'm not a slap player but do occasionally like to hit it like I love it but it's done me wrong. The Effectrode only has two knobs and a limiter/compressor switch but it can do a wide range of compression - it's not mega complex and has no lights but the positive qualities it brings to the tone of what ever I play it through (PA, sh*tty peavey practice amp or decent combo) is worth the money. A P bass with flats going into this is just heavenly!
The PC-2A is a big warm hug of a pedal which evens out the attack without choking the dynamics of my playing. I'm recording this weekend and we're gonna try it with acoustic guitar, vocals, electric guitar and bass - a total work out
I can't say it's the best comp out there but it's perfect for my needs.