I'm upgrading my boat to shore transportation, too. We have two kayaks we use, but we're adding a dinghy with a motor.
I just bought the motor, a new Suzuki 2.5 horse.
I'm been going back and forth, like everyone does, on whether I want a hard dinghy or an inflatable. Finally decided on inflatable. I won't go into the trade-off between the two, as it's been done to death.
Having decided to go the inflatable route, Hypalon or the equivalent is my choice over PVC. Holds up to UV. For a reasonably priced Hypalon inflatable, I'm not finding a better value than Achilles. Check out Defender.com, as they have the Achilles with all the stats and pricing, along with Avon, Bombardier, etc.
We're keeping a close eye on the weight. I already have a 10 foot Avon that I got for free in great shape, but even without its very heavy plastic floor it weighs a little over 95 pounds. Rolled up, that's an ungainly 95 pounds for one person to wrestle. An Achilles, 8'8" weighs, if memory serves, about 66 pounds including the rollup floor. I'm thinking about going small and getting the 7'6" at only 57 pounds.
My motor's 40 pounds. 6, 8, or 10 horse engines weigh plenty more. You get to go faster, but at a greater cost in weight than I'm willing to pay. Not so bad lugging a 6+ horse on land, but transferring from where you store the motor on your boat to the dinghy is where it gets fun. Sploooosh