We saw the 2390 at a show today and loved it. So much that we put a deposit on it pending a test drive next weekend. We also wanted the time to research. However in researching we saw the 2380 on-line and loved the more enclosed bathroom. But there are no good pictures of the bed area so it is hard to truly compare.
We have a TS2390 so I'll try and answer your questions. Before that a few general comments on the 2380 based on what I've seen on-line.
Bedroom:
You will lose some, I suspect a
lot, of the overall storage space in a 2390 by going with a 2380. We have shirt closets, and drawers, on both sides of the bed. Plus a large overhead three door cabinet between the the two shirt closets. And four drawers under the bed. The 2380 doesn't have any of that from the photos I've seen. With the 2380 you do gain a "hall closet", where the 2390 shower is located, but I don't know if it has the same capacity as
all of the 2390's rear storage. Second you lose the walk around bed and have a corner bed in the 2380...that is a show stopper for us.
Bathroom:
The enclosed 2380 bathroom is a step back in my opinion as well. Instead of a larger corner shower you revert back to the smaller rectangular unit. And you get to step around the toilet getting in and out of the shower. With our "split bath plan" one of us can be in the "bathroom" while the other is in the shower.
Nose / Cap Area:
With the 2380 placing the television up in the nose, versus in the kitchen hall on the 2390, it kills another large storage area we have in our nose cap with the 2390. Definitely not an advantage in my view.
Summary:
One of the advantages of the 2390 is it has a lot of interior storage space and the CCC to be able to use that space. The 2380 just takes away too much storage space for very little gain in my opinion. I'll stick with the 2390...
Please post your overall review of your unit. Problems you have had along with things you have been pleased with. Also please discuss any modifications you have done.
Overall we have been very pleased with our 2390. We down sized from a larger Class C and the 2390 has worked very well for us as a "couples coach". We had some of the typical FR quality control issues you read about but everything has been addressed either by FR, at the FROG Rally, or by our local dealer. We have not yet experienced any "show stopper" type issues. Without any slide outs or leveling systems those are less likely to occur anyway...
We spent fifteen consecutive nights in our 2390 at last years FROG Rally and had no real concerns about space. You just learn to manage who is where when in a small RV like the 2390!
What we really like:
The Ford Transit is a pleasure to drive. Small enough to easily get around town or cruise on the freeway it is just a very good chassis. We have the 3.7L gas engine and have averaged anywhere between 12 to 15MPG based on traffic and speed. The Transit has plenty of power to drive thru the mountains in TN and KY on I-75 with the cruise set at 65MPH. We downshifted into fifth gear a few times but held our speed. One really big advantage of the 2390, for me anyway, is my wife doesn't mind driving it. It is a pleasant change to not do all the driving!
The AC/DC/LP refrigerator works great! It is one of the best units we have had in a long time. And being able to run it in DC Mode while driving keeps everything nice and cold.
The bedroom has plenty of space for being a smaller unit. As I mentioned above a corner type bed would be a show stopper for us. We had that and do not care to repeat the experience.
The A/C keeps the 2390 nice and cool. There isn't a lot of space to cool down, compared to larger units, and the A/C works very well. The Truma furnace also works very well.
What we don't care for as much:
The Truma Combi water heater and furnace. Our issue with it is the small water tank size. Do not try and do dishes while your wife is in the shower...

On the plus side it recycles very quickly when it is configured correctly. And you can program all sorts of neat features. It is a good furnace and much quieter than traditional RV furnace.
The shower. While I prefer it to the 2380 style the shower has a learning curve. It is effectively on a raised platform and you step down back in to the "hallway" when you get out. Not a big deal, just have no slip rugs and mats, but a little "weird" at first. The 2390, and 2380, are so small I wouldn't worry about stepping out in to a cold room. The temperature will be the same pretty much all over...
To see the modifications we have made to our 2390 click on Registry, to the left under my info, and it will link you to our Registry page with all the info.
Have you installed a tow hitch for a hitch cargo carrier? If so how much did it cost?
Not yet. However do I plan on adding one so we can carry our bikes. The Coachmen Class C's on the Ford Transit chassis do offer a factory hitch rated at 2,000 pounds. The frame extenders, used by FR to extend the Ford chassis, are not rated beyond that so pulling a TOAD is pretty much a dead issue. We don't care as the TS is small enough for getting around most places. And when we are going to be in place for several days, like at the FROG Rally, I just call Enterprise for a car...
Have you installed solar panels? If so how much did they cost?
Have you upgraded to 2 batteries? Were there any problems fitting them into the stair compartment?
No and No... We are not "campers" per se, we use our 2390 to tour. So we generally have hookups and do not need to extend the battery capacity of the 2390. It does look like there is plenty of space in the stairwell compartment for a second battery.
They were selling the 2018 for $59980 with Transit traveling package, bedroom TV, Maxx Air Fan Bedroom, and Arctic Package. Which appears to be the widely available price on the internet. Has anyone negotiated lower? If so we may try to get them to throw in an extended warranty.
That sounds like a good price from what I've read and what we paid for ours. We also have Full Body Paint which is nice but too darn expensive...
We will be glad to try and answer any specific 2390 questions you may have. If you want to chat about it PM me a phone number and a good time to call...
Hope my very opinionated answers

help you out a little!