Is lunch at 58 Tour Eiffel worth it?

I have not eaten there, but it seems to get good reviews on Trip Advisor. I suggest you go to this site and check them out.
There are also customer photos of the view, the food, and menu with prices.

The answer to this question in all past threads has been yes. The food is good, not great, but what you're really paying for is location. There's a thrill to having a nice sit down meal on the ET imo, as long as your kids will appreciate it.

What Susan said. You'll overpay for average food but you'll be eating it in the Eiffel Tower.
We ate there on our first trip to Paris. We both enjoyed it but not enough to do it again just for ourselves. We did, however, take our granddaughters there on a later trip and all four of us enjoyed it.
So is it worth it? It depends on what you like. It seems to me that a person already has some inkling, before they go, whether or not they're going to be wowed by an experience like that. I can picture some people being thrilled and others thinking it a waste of time.

Depends.

If you get a window seat that helps otherwise it is not worth it. our last visit in Sept. 2015 was a middling meal with terrible service and professional photographers taking photos and trying to sell them for exorbitant prices. Ugh. Like being on a cruise ship.

We put our names down for a window table as soon as we got up the stairs and returned after going to the top. Otherwise reserve ahead for a window.

There are way better restaurants for the price. But it is the Eiffel Tower and it's an experience. And they know it! The museums at Trocodéro have nice cafés with views of the Eiffel Tower. We will go there this time.

Enjoy!

I think Sandra is right about the window seat. It makes a big difference in the experience.