All of the places you mention are run by management with individual trainers providing day care for the horses - things like turnout, grain feeding, etc. So care is going to be a hybrid of what the barn management provides plus your selected trainer.
The multiple trainer situation almost always creates some drama. If you are fortunate, your trainer will absorb most or all of it and it will not affect you much. All of these places have enough different rings to ride in that you shouldn’t have too much drama with that, but you should ask what restrictions there are on where you can ride and when.
I have been a boarder at Middle Ranch and Hansen Dam, and I’ve shown extensively at Paddock.
Paddock is more landlocked but I have a couple of friends who are there and seem content. If you can get there more easily and you find a trainer that fits, it could be a good option. Their turnout situation was the somewhat minimal last time I was there. Access to Griffith Park trails.
Hansen Dam is having shows and can be very convenient. It is very exposed (read hot) in summer but it’s a very well built facility and I was reasonably content there. Access to the Hansen Dam area trails. I understand they have redone the footing in the arenas since I was there, which was needed. (BTW, there’s a puff-piece article on them in the current free Riding magazine at tack shops.)
Lower Middle Ranch is very posh with grass and trees and a really gorgeous setting. It has a covered arena and engineered outdoor arenas. It’s expensive but when I boarded there it was competitive because there weren’t extra charges for feeding hay, tack stalls, etc that we’d paid elsewhere. There is a clubhouse that at the time was available to boarders … which was nice to be able to shower and then go to work. Trying to ride in the covered if the rains are really nasty with all the horses trying to use it is … a Thing. There is access to the Hansen Dam trails. There are strict hours to this facility and a locked gate at night.
Upper Middle Ranch is more workmanlike and I haven’t ridden there.
In general, if you want turnout for your horse, I’d strongly suggest considering the 12 x 24 covered pipe corrals at places that have them. They’re nice for the horses, airy, and give them more room to move. Half covered, the outer area will be muddy, which is a lot less nice. The downside is that you might be separate from your barnmates in such a setup.
So I think you could be happy at any of these places facility-wise. The bigger issue is to find a trainer you would like to work with and also budget. Board is high. After board you may also have to pay:
- fees for turnout
- fees for hay or tack storage
- fees for blanket/unblanket/fly mask
- training/lesson fees.