In general, there's no reason to ever solder AND crimp anything. A proper crimp is both airtight and at least as strong as the wires you're crimping. The second crimp you add to a crimped joint isn't to keep the joint from falling apart like most people think...it's just to immobilize the wires since the part that's crimped is practically solid and is just as "brittle" as a soldered joint. Adding solder to such a joint will do absolutely no good for "strength" or conductivity (nor will it hurt, typically), and will just increase the likelyhood of making the joint brittle.
A properly soldered and strain relieved joint is just as durable and electrically sound as a crimped joint, and crimping a properly soldered joint will do absolutely no good...in fact it will negatively affect integrity of the joint if anything.
In terms of reliability, it's infinitely easier to make a perfect crimp with a ratcheting crimper than it is to make a perfect solder joint with the best Weller or Hakko money can buy. How do you put a Q/A stamp on a solder joint? Looking at it doesn't work. You have to trust your trained technicians and destructively test samples (yank on them, take cross sections, etc etc). Crimping, on the other hand, is easy to inspect...did he use a calibrated crimper? Yes? *STAMP*.
Personally, I intend to crimp everything I can with a decent crimper because it's pretty much a no-brainer to make a joint that will outlast just about everything else on the airplane.