Well, since I don't have a Subaru, and am biased by my Kohler's dependability, I'd have to think long and hard about it.
From what I've heard, the Subaru's don't start well when its cold outside. And by cold, I mean way below freezing down to -5 or so. That's when I need the machine the most, as I have to plow the drive to get out to go to work to make money to support my family. So does my wife, so she's counting on me as well. In summer, its no big deal if the machine doesn't start. I can mow the lawn tomorrow. Not so much with snow.
My garage is unattached, un-insulated and unheated. I don't want to go out there and apply special means to get it started. Block heaters, tank heaters, space heaters, quilts, blankets, etc... its bad enough that I occasionally use starting fluid below -5 if it doesn't pop after a couple tries, as I have to open the hood and remove the air cleaner, start it, and then put everything back.
I do not know which engine is made better, will last longer, is easier to service, etc... I know I can get parts for the Kohler locally at several sources. The Subaru, not as many places, but they are getting more common.
Now to the question of the electronic fuel injection, and this isn't specific to either brand.... Supposed to start easier (does it?), and use less fuel. However, I cringe at electronics in lawn and garden (and AG) equipment. When it fails, how do you diagnose it and are the parts available, and, most importantly, how expensive are they compared to a carb?
If I had one with a Subaru, I'd probably go for another Subaru with more HP and EFI, put a Subaru exhaust system on it and modify the hood to make it fit. I'd put in plenty of heat shielding to keep the muffler heat directed away from the engine and hydraulics. My Kohler has a Kohler exhaust system and the pipe exits directly out the center of the rear of the machine. There's a Kohler heat shield between the muffler and the engine, too. In my opinion, their home-brewed exhaust systems are a problem. They're restrictive, too many bends and corners and probably hinder performance. They need to seriously re-think using the Subaru in this application.
Anyhow, its all speculation until I get my hands on one with a Subaru, so take it for what it is... my opinion, not fact.
