Search under D-Tar and you will find a lot of info.
I liked the D55 with D-Tar that I had a lot and used it for about 20 gigs with a Baggs paracoustic into a small PA. It's a great undersaddle pickup; lots of headroom, not much quacking.
The factory installed (at least in Tacoma) Lock'n Load D-Tar systems are a bit heavy. Some people don't care, some do.
Personally, I think it all boils down to what you are used to, as well as the instrumentation on the gigs you play. If you are trying to cut through even a small/quiet band, undersaddle pickups work great. Other pickups that I have used, like the I-Beam or some of the Fishman or Baggs soundhole 'magnet' pickups might sound better in a solo/duo guitar or a singer/songwriter setting, but will often feed back quickly in a band setting.
On the other hand, if you are playing a mostly electric guitar gig and just have a need for an acoustic on a few songs a gig, a magnetic sound-hole pickup like a Sunrise can come in handy, if only because you can plug it into the the same amp that you are playing electric through. For example, I did about 12 gigs in '09 with a four or five piece band. We had four vocals, drums, bass, keys, banjo, and two guitars competing for the 8 XLR mic inputs on the '12 channel' Mackie board we were using. There literally wasn't an extra input available for the acoustic, so I had to plug into my Fender electric guitar amp to get into the PA. The D-Tar with a preamp sounded good, but a magnetic pickup (like a Sunrise) sounded better. Why? Well, the amp was designed to amplify magnetic pickups like on a Strat, Tele or Les Paul and believe it or not, that's exactly what a 'magnetic sound hole pickup' is!!
Anyway, good luck on the Great Search for the Right Pickup. The only certainty is that, no matter what brand or type of pickup you buy or use this year, in three years you will have been through two or three other pickups.