Propitiatory parts can be slightly higher priced that standard parts. But they also have a track record of lasting longer.
How is a Marquis spas 5 year old proprietary topside made by Balboa something that will "last longer?"
What do you mean by that? So Proprietary circuit boards last longer?...HMMMMM
If your topside is made by balboa for Marquis it can likely be replaced by another topside. However that DOES not mean it will be the same topside that Marquis buys from Balboa.
Do you think the topside supplied to a company like Strong Spas for Costco by balboa is the same topside supplied to Marquis?
Do you think a company like Balboa makes several levels of quality topsides?
Some spa companies tell manufacturers what they want in the topsides made by Balboa for them. Other companies tell Balboa how much they want to pay for their topsides. Do you think Balboa uses the same topsides for both companies?
Have you ever heard of the term "seconds" Every company with a quality control program has certain standards that have to be met in order to ensure their product is top notch. Some don't meet these standards. But are they disposed of? Not necessarily.
To make a run of lessor expensive topsides there are a lot of corners than can be cut to save money in the manufacturing process. This allows the manufacturer to sell them for less and still remain profitable.
Marquis is not the kind of company that tries to save money by asking for a "less expensive" topside. They are they kind of company that likely tells Balboa to meet their specs. for their topside. And that means more than just putting their name on it.
Make sense? The only way to know for sure is to get the part number off of a Balboa topside and compare it to a replacement.
I went to Walmart and looked at a Sony 55" TV that had the same specs as the 55" Sony TV I looked at from Best Buy. The part number was 2 digits different but both TV's looked exactly the same. Huh? 220 bucks different in pricing. Huh?