I'm a big flatwound guy. I can't really rank them on a 1-10 system though...
LaBella Tapewound Flats: Bright and smooth in terms of tone. Feel is very nice as well. The tone on these never changes because of the wrap. Not really thumpers but they're good for playing melody. Harmonics jump out of these strings.
LaBella Jamerson Signatures: Ultimate thump machines in my book. Very dark and deep sounding, very old school tone. These take a bit to break in, but when they do, you're set for life.
LaBella Deep Talking Flats: Some say they sound the same as the Jamerson signatures, but I tend to disagree. An old school flat for sure, but they don't make your tone as meaty if you ask me.
Rotosound Jazz Flats: Very bright and crispy when they're new but they mellow out kind of quickly. Not very thumpy but they sound good when you're playing a lot of fast lines. Think of Roger Waters tone when they're broken in.
Rotosound TruBass 88s: Nylon wrapped flatwounds, very smooth, dark, and thumpy. Think of Paul McCartney's tone on Let it Be. Very smooth feeling string.
Fender Flats: Deep sounding, but to me they were always a little on the hollow side as well.
Thomastik-Infled Jazz Flats: Low tension, harmonically pleasing overtones. These are some of the best sounding flats I've laid my hands on BUT then low tension gets me.
I'll post more reviews later if I can...