I know you have a specific question, and hopefully people will chime in who actually know these particular speakers, and maybe that'll be helpful. But you also need to keep in mind that whoever does that is probably going to be giving you their thoughts on the only monitors they've ever owned, lol. One guy may "LOVE" his Yammies because he's never mixed on anything else.
All I can say is that I prefer having nearfields with 8" woofers. They'll go down lower, and they'll produce the stuff above 45Hz more accurately...and they'll fake the stuff below 45Hz well enough for you to hear what needs to be done!!!
But I know plenty of people mix with 5" woofers...I just can't.
I have owned some JBL 8" monitors before...they sounded great, which was a problem. They were very "flattering" in the low end, but only at specific frequencies, so depending on what key the song was in, my mixes would either be really bass light or really bass heavy. Drove me nuts until I figured it out.
I'm not saying those JBL monitors would do that. I have no idea.
If you want to see a wider cross-section, you might run a search on Gearslutz...i know they have several epic monitor threads with reviews in the "low end" section of that board.
I will offer up an alternative. The 2nd Generation of KRK Rokit 8's were getting really good reviews, and I picked up a pair on MF awhile back. I wasn't expecting much, but I couldn't be happier with these monitors. Front firing ports have helped with the low end decisions a whole bunch. I already wrote a poor man's review of them around here somewhere, but the bottom line is that whatever changes they made in the "G2" series are apparently fantastic. You can get them used from MF for only $20 more per speaker than what you're looking at paying. Look here:
KRK 8" G2 Monitors @ MF
One more thing...monitors are very personal, so it's good to get a kind of a wide cross-section of people that like a product so you have the best chance possible of being pleased. Gearslutz is a good resource, searching here might do you some good too. I haven't seen a bad review yet of the KRK G2's, and I frankly can't believe they're selling them as cheaply as they are, but don't listen to any one guy who either loves or hates a speaker.
Good luck.