We haven't had time to do proper battery testing, but in every other meaningful metric, we found the HX1 outperforms the Prime. For one thing, Motorola's set offers a simple, dedicated controls for call send / end, volume up / down, and noise reduction toggle (Moto calls it "stealth mode") plus a physical switch for turning the phone on and off; Jawbone's oversimplified two-button layout has always befuddled us, partly because we can never remember what combination of presses does what, partly because activities like pairing always seem like they're more complicated than they need to be. We also prefer the HX1's standard micro USB charging socket to the Jawbone's proprietary connector -- there's one less dedicated cable we need to tote around, and we find that it can be tricky to get a solid, reliable connection with the Jawbone's dock-style socket (it's a problem that's haunted them from day one, so we're not sure why they haven't moved away from it by now).
Though a clear plastic earloop can be connected to the HX1 to help secure it to the side of your face, we found that it's totally unnecessary because the actual bud -- the part that contains the speaker and the bone conduction sensor -- goes quite far into your ear canal and helps to lock the headset in place. Furthermore, the unusual bud shape serves to make calling far more realistic in extremely noisy environments because it's completely blocking out external noise in that ear and channeling sound as deeply as it can. The Prime, on the other hand, makes a stronger case for using the earloop -- the bud doesn't actually enter the ear canal at all.
We look at it as the best of both worlds. CrystalTalk is good enough for 90 percent of environments and situations that you'll encounter, and for the other 10 percent -- like when you're in an iron foundry or at a Cannibal Corpse concert, for example -- stealth mode saves the day. We're not sure exactly how much of the HX1's tech came from its Nextlink licensing agreement, but let's put it this way: Motorola's either designed a terrific product or made a terrific purchase.