Worth of a covered slip berth?

Depends on the location and slip. If it's a wooden dock and wooden structure and not properly vented or to today's standards, then it's worth negative as it's a fire risk. If it's a nice slip, floating concrete docks, metal structure, vented and up to current standards plus the tenants carefully chosen and monitored, then of great value. Can't put a dollar value either way.

My view is what I wrote above. There are many on the TN River and the Cumberland River that are far below today's reasonable standards and fire hazards. Lake Cumberland had fires before improving coverage and adding more houseboat rules. Guntersville Lake had a marina fire about a year or so ago. View and protection do not matter at all until safety is determined.

How are you going to fit it under there if you have outriggers or a tower? Covered is nicer, but then limits you in the future to what size boat you can fit.

Are you a cruiser or a hanger? I'd imagine marinas open to the sun tend to have more of a social nature with people hanging on their boats. Although I've never had a boat in a covered slip I can't imagine hanging on the boats there in the shade. So are your plans to just come to the boat to go somewhere or work on the boat or are you looking for a marina lifestyle? Certainly a covered slip will cut down on boat washing, but I suspect a sportfish has seen very few covered slips in its life..

I've had a boat in a covered slip before the lake we were on pretty much eliminated them. However, that slip is very well done. Nice metal structure and staggered heights giving an area for fire to escape. I wouldn't hesitate there and, within reason, would be fine with any premium cost. I'm curious but are the decks wood? Doesn't make me concerned with the top but simply such a nice dock otherwise.

The slip you showed is plenty high to give a great view and days you're not yet on the water or just returned, you'll love the comfort.

In that case covered will mean less time spent washing the boat (except from pigeon droppings). Will sharing the 130' slip require the lead boat to move to get out every time the 2nd boat wants to move? Otherwise it's kind of 6 of one or a half-dozen of the other. One other consideration is that in some marinas the further out you go the weaker the water pressure and electric

On an outside end slip you are also exposed to all the boats that transit in/out of the marina and have to pass by you. That adds risk, especially from intoxicated drivers. I would do the better protected covered slip in a heartbeat. I wish I had that option in my area!

I have been in a covered slip for about 10 years. My wife was against it because she likes the sunshine but she came around pretty quickly.

Up side it keeps the sun off the boat which prolongs the life of the entire exterior, in my case the wood work too.

Also helps the AC when the shed temps are lower than the sunny side.

You can piddle around working on the boat or sit out on the deck in the rain too.

Cons, spiders and birds.
We use the Starbrite spider and bird remover for cleanup and it works really well. Does not take the wax off either.

LINK

I've been under cover several of the years I've been boating. I never experienced the boat stays cleaner phenomena though, Unless the marina has active bird and spider mitigation in force I found that the boat needs cleaning more often under cover. The benefit is the boat stays dryer in light rain events and there is less sun exposure. My wife hated sitting in a barn on her boat so she was never interested in weekending on any of our boats when we were under cover. All in all not worth the extra costs IMHO
Cheers

The best covered slips have curved corrugated metal roof panels without the framing below that solve the bird problem. They probably don't work up north in snow and ice, the panels are secured to gutter troughs on piling's.

Definitely not cleaner in my area.
In spring time, if it is dry, the dust from plowing field rests all over the boat along with pollen.
Some years, really heavy pollen.
No rain to naturally wash it away.