Looking at two types of trailers, 6/7x14 open aluminum and 6x10 steel frame enclosed.  The enclosed is $500 to $1000 more.  Having a tough time deciding between the two.  Obviously they each have benefits.   What would you choose and why?

[2015 Z Force 800 53/Trail EPS]

Because these Motos are taller then most others, the door height on a lot of enclosed trailers is a problem so check that closely..especially if you want to add larger tires and/or a lift. The 10 foot will just be enough..my 9.5' flat bed lets a little peak over the edge. With a larger open trailer there is more you can do with it then just haul the toy around. I would pop for a 7x16 tandem with a ramp. Not quite a car carrier but most bases will be covered.

Looking at two types of trailers, 6/7x14 open aluminum and 6x10 steel frame enclosed.  The enclosed is $500 to $1000 more.  Having a tough time deciding between the two.  Obviously they each have benefits.   What would you choose and why?

I have a 7 x 14 single axle to haul my Z500 with side ramps to pull my atv in the front from the side. I would have opted for a dual axle like NMK suggested, but the Laws here in WV, taxes, fees, having brakes, and extent of use, etc. kinda dictated my decision.  The smallest I'd go would be a 6 x 10 single axle if your Z is all you plan to haul. 

Any pics of them loaded?

Mine is a 14' single axle with side and rear ramps.  I purchased it for not just hawling my Z8, but multi-use.  With that said, I am now thinking about trading it for an enclosed model.  We started going south for a couple of months during the winter and it would be nice to have the security an enclosed offers.  Plus, I could put my foot lockers, tools, etc. in there without concern.

Considerations:

Does the tow vehicle have a trailer brake controller?
Will the trailer be stored inside (is there room)?
Is trailer rated for 3000lbs+?

I bought a 5.5'x10 open aluminum trailer (2900lbs) because I keep it in the garage and didn't want it to take up more space than necessary. I also added electric brakes which I highly recommend.

I wish I had an enclosed trailer to keep the road dirt and winter salt off the machine, and to be able to store the toy in the trailer outside, but that was big money and I would have had to order a custom door height (6.6') to get the toy in comfortably. Having an enclosed trailer offers up some alternative uses as well, like outfitting it for camping trips with the toy (poor man's toy hauler), or being able to use it to move stuff in bad weather. It also keeps the wind off the machine during towing (I drive too fast ;-).

I recommend aluminum trailers just because they don't corrode/rust or shed paint, and the lighter weight is easier on mpg.

It's a 2500 silverado diesel that is the tow vehicle.  I was originally thinking enclosed so I could use it for storage.   I think i will be going steel open.. yes they can rust but aluminum will pit.  Only advantage of aluminum I see is lighter weight. 

I have a 16ft open deck trailer but honestly, most of the time I just drive it up into the bed of my pickup. Tight fit but works great.

What size bed?