I have an aluminum road bike from the early 90's and was thinking of upgrading the wheels for better performance and looks. The bike is in great condition, is it worthwhile to upgrade or not?
The only wheels that interest me at the moment are the Mavics. My bike is a 14 speed. I do not want to spend $1500 or more for a new bike at the moment, though temptation does arise.

imho upgrade. But I am bias to spending money on things you enjoy

Don't think youll get much of a boost in performance. Looks on the other hand.. looks do count for something

What are you hoping to get out of the upgrade? It seems to me that it's likely that the money would be better spent by putting it towards a nice year end sale on a CAAD10 or other new, quality entry level bike.

May I inquire why Mavic only?

Here's your problem. It's not worth buying a wheel with a 7 speed hub. The wheel's your looking at have 8-9-10 speed compatible hubs, and don't work with 7 speed cassettes, at least not without some hacking.

So your options are limited, without upgrading a bunch of stuff. If you've got down tube shifters, you can go with the new wheels, put an 8 speed cassette on, 8 speed chain, and run it in friction mode.

If you've got brifters, you need new 8 speed brifters as well.

You've also got the issue that you've likely got 126mm rear spacing. You'd need to spread the rear dropouts to 130mm which can be done, but its debateble whether you want to do it to an aluminum frame.

At that point, I'd just keep the bike as it is, ride it, until you save up for its replacement.

Stick with the wheels you have OP and save your money. Your bike as much as you like it is a bottomless pit to upgrade. If the wheels are out of true, practice turning them.