It's not really a big issue. If you lose your connection that easily you should get a different model. You just have to remember that the transducer has a battery in it, which naturally must be replaced for it to continue working. Do a search on here and you will come up with all of our little (and not so little) arguments of which is better.
I recommend a wrist mount no matter what kind you get.
Thanks for mentioning that you want to do tech diving in the future. That makes it a lot easier to suggest things.
Having read that, I recommend that you seriously consider a backplate/wing/harness system. Basically that is what was shown in the pictures I linked you, it's a steel or aluminum plate with a channel for your spine, which bolts to a wing, bc for non-techies, with bolts and wing nuts. The system is held on with 2" webbing, which is extremely durable. And it allows for a completely custom fit. They are the same as or cheaper than most BCs, and here's why you should get one:
Right now with single-tank diving, you would get a single-tank wing. This is a small, compact wing that wraps around the tank and supports it. Then, when you get ready to do techical diving with doubles, you simply buy a doubles wing that will bolt onto your current backplate/harness and away you go. And you can get backplates in a variety of weights, from 2 pound aluminum to 12+ pound stainless. This helps with your trim since you get some weight off of your belt and spread it evenly over your back.
By going ahead and getting a BP/W (that's the abbreviation for them) now, you'll end up saving a lot of money by not having to buy another complete setup for tech diving.
If you're going into tech, I would steer you away from the AI. (I know, I know, I just talked it up, now I'm knocking it down.) Brass SPGs seem to be more durable for tech diving. Generally, here's the setup for a tech dive (deco, doubles, penetration):
Doubles wing
Backplate
Harness
wet/drysuit
weightbelt if needed
two regs on the doubles, one with inflator and backup reg, the other with drysuit inflator and primary reg.
Can light, 2 backups
wrist mount computer, compass, backup bottom timer/depth gauge, all wrist mounted
slate and backup slate with deco plan and backup plans
reel, spools, lift bags, and a few more odds and ends.
So basically, you can cut down your 'move-to-tech' price by getting the things that are rec and tec compatable now. As a side note, all this stuff can be used for non-tech dives too. Can lights are great for night dives and looking in holes (imagine a car headlight on your wrist). And all the other stuff works fine too.
Hope I haven't confused you too bad.
Here's some websites with pricing and info:
www.halcyon.net
www.oxycheq.com
www.extreme-exposure.com
www.covci.com
www.fifthd.com
And quality used equipment is always delightful.