I've had a 7000 and been totally satisfied.
I considered the aluminum trailer but ruled it out for 2 reasons. First, the cost got me close enough to an enclosed trailer, which I bought.
Second, there are those that have had problems with salt. Yes, others have not and alot of snowmobile trailers are aluminum. But, I didn't want to chance it.
Back to your question, if all you're gonna haul is your jeep, don't spend the extra money on the 10,000.