We were motored out of the grand to Pearce Ferry this year by a guy that had the Lehr 5 HP propane motor, it was a cantankerous thing, built VERY cheaply, as one would expect from a POS made in China.
That being said, once it actually got started (10 min of bleeding, pulling and cursing), pushing an 8 boat barge, we averaged 4MPH (by GPS), sometimes got as much as 5MPH but no faster, I was impressed. Very glad to have it along when the breezes kicked in. The motorman never got past 1/2 throttle as he said in his experience more throttle only burned more propane, without providing more speed. We burned 4 gallons of propane on the motor out.
The big bonus to me is, you don't have to smell gas all the way down the river, AND you have propane along anyway. I'm going to buy a Tohatsu for 2 reasons. While I haven't actually seen one of the propane units, I've seen many of the gasoline ones, and their quality is much better than the Lehr, by leaps and bounds.
The second reason is the available shaft length of 25 inches. You can always get it out of the water using the trim adjustment if you have to, and I've had issues trying to get my current 20" long shaft gas motor INTO the water, especially on the back of my Avon pro using the standard Avon motor mount that slides into the motor becketts. I have a Cabellas adjustable mount on my 16 foot cat,
but it's spendy, and hangs the motor out from the back of the raft anywhere from 9 to 15 inches, making a tiller extension handle a necessity. I've NEVER seen one of these, usually homemade, like mine made from a busted cataract oar shaft, that was worth a damn, and makes it a WIDE swing to make a tight turn, usually in a critical time, hard to do while seated, and when you stand in a raft under motor, there's a chance you might be a sudden unintentional swimmer, not fun.
The pricing is comparable with the Tohatsu 100 bucks cheaper on sale, the warranty I think given the number of Tohatsu dealers and the comparatively few Lehr dealers would be easier to deal with should you need it. One more thing, the Tohatsu has a 5 year warranty, the Lehr 3 years...
A hundred bucks more for the Lehr, shorter shaft, shorter warranty and I can't find a stocking dealer anywhere near me, they all say buy online, which is fine I guess, but if they don't stock the motor, is there a chance they stock replacement parts?
Tohatsu dealers are all over CO and UT, which is pretty much where I primarily boat, and they stock the things, I'd still buy over the internet due to the pricing. Perhaps one could get a deal in the wintertime, but I'm lazy...
One more thing, no matter WHAT motor you purchase, get a spare metal prop or 2 especially if you're going to do Deso at low water, a couple spare shear pins is always a good idea as well. I've seen so many of the plastic props shear blades off faster than a fat chick tearing thru a bag of Cheetos, leaving the owner SOL without a spare prop, as recently as last weekend.
I've motored the entire length of Deso in bad weather with a metal prop (aluminum) and while hitting things here and there, usually sand bars, but occasionally rocks in places like 3 fords, and the daily section where it gets wide toward the end, that I wouldn't even think of doing it without a metal spare.
My 2¢, your mileage may vary.
Pray for snow this winter!! Hope this helps...