I have owned a number of trailers and for my use I will not buy anything smaller than a 24'. I have had 20 footers and you are cramped with anything longer than a camaro and the 24 just seems to balance out better. I have had a 24 foot Featherlite and a 28 before I bought the 24 Featherlite from you. It might be a little overkill but if I am going to pull an enclosed trailer I do it with a dually truck. I have done it with 1/2 ton and 3/4 ton trucks and there something to be said for the comfortable feeling you get with the stability and braking power of a dually. For my money the Featherlite is the way to go with enclosed and Tommy aluminum for an open trailer.

My trailer is a 20' Alum-Line with 3' wedge. The wedge really adds to interior space, like for buying roller and loading the engine/trans etc. up front.
Alum-Line was founded by a former co-owner of Featherlight and manufactured on joining property in Cresco IA.
I ordered it 6" narrower and 6' ceiling height for reduced drag, I recommend a 5'w escape door properly placed so car doors can fully open.
I've towed it over 90K miles through 42 states with only tires, brakes and wheel bearing packs.
As was mentioned, what you are towing with and what distance should have an influence on trailer choice. I normally average 8-9K per year (but not this year!)

Thanks for the thoughts everyone. I have been looking at ATC, but it seems 16" centers is what I see. To address the truck question, I have a 2018 GMC 2500 Crew Cab 4x4 with a Duramax. I should have plenty of truck to pull it.

Anyone prefer a steel trailer?

That was my understanding as well, 3,500# = 5 bolt, 5,200# = 6 bolt. A 24' trailer with a full size car and 3,500 axles you won't be able to pack a snack without being over gross.

I had a 24' ATC and replaced it with a 22' Jimglo. It was 1000lbs lighter and I tow it with a 1/2 ton Ford Raptor with ease. The body is a honeycomb composite. Built in a prison by prisoners in Arizona. No seams as each side are one piece. Roof can be walked on. Expensive but very well built.
https://www.jimglo.com/

I prefer a steel trailer simply because of my cost vs. use scenario. When I was shopping, aluminum was almost 2x the cost of the steel trailer. If I hauled a lot, I would have invested in an aluminum trailer, but I may use mine 3-4 times a year, so the cost savings of a steel trailer won out.

Wow Charley, that thing looks amazing.

That's exactly why I bought a steel trailer.

I went with Haulmark Autotransport 24' steel. I love the trailer, but will say there are a few quality issues. Haulmark isn't even made by Haulmark if you can believe that. The name of the company who built it is on the ramp. The bones and basics are great, but trim details are poor. For instance, the tire storage hole in the floor has mitered aluminum trim that doesn't fit well. Around the doors inside is the same. Not a big deal, but when you're paying for it... Aluminum would be nice for weight, but my Expeditions tow mine loaded well. I included a scale ticket so you could see what it looks like with weight in it behind my 07 Expy. Now, my 17 Expy tows it even better.
Yes, I know my 69 is in backwards and that's a huge no no, but I had a motorcycle up front.
A couple of things that were must haves for me:
1. Oversized get out door. I would love to have one where the side opens fully. My door is a little high. It does help getting out.
2. Lowered rear end. Called dove tail.
3. Electric trailer jack. Sooo much nicer than the crank. The factory one was cheap.
4. In floor/inside spare tire storage.
5. Trailer Aid drive on ramp to change tire easily without having to jack up the trailer.
6. Weight Distribution and anti sway hitch.
7. MaxAir II vent so you can leave the roof vent open all the time.
8. E-track everywhere...
9. 5,200 lb axles a must.
10. Lowered and wider side entrance door.
11. Winch.

If you notice in one of my pics there is a 1"x6" board back by the ramp door hinge point. I plan on adding an aluminum piece that automatically flaps down when the door is opened.

https://live.staticflickr.com/1892/4...d9745660_k.jpg20180605_144839 by Dave H, on Flickr

https://live.staticflickr.com/1860/4...7969c82b_k.jpg20180626_141548 by Dave H, on Flickr

https://live.staticflickr.com/1898/4...cdabd38a_k.jpg20180625_192221 by Dave H, on Flickr

https://live.staticflickr.com/4421/3...4c5c9afa_b.jpgMaxxAir%20II by Dave H, on Flickr

https://live.staticflickr.com/1866/4...171bd1c6_b.jpgCat Scales with 69 Camaro 063018 by Dave H, on Flickr

I have an alumn enclosed made by Tommys in Ada, Ok. They built the very first alumn car trailers decades ago. Mine is a 1986 with several hundred thousand miles on it. It is a 22' plus the nose. The axles were slid back 2' as it has a lift system in it to haul 2 smaller cars if you wish with the second one 'biggy backed'. I pull the race car 8-10 weekends a year in it. It is nice and light with plenty of room with the nose. Mine does have doors on both sides too which is nice

From what I have seen on used trailers. If they are kept nice, they bottom out on price at about the 7 year point. So if you can find a nice, kept in doors, 7 year old alumn trailer, what you pay for it is what you will sell it for later on too.