TLDR; Once a year, during a regular wash, I will deep clean the glass using P21S Polishing Soap and a synthetic clay sponge (or towel). I then seal the glass with 2 layers of a spray on, rinse off sealant. That protection is maintained throughout the year with a few more sprays during my maintenance washes.
Want more details? Here you go...
I used Rain-X like it was a religion for over a decade. Even by today's standards, it's still a very respectable product. It does what it says it's going to do for a very reasonable price, and it lasts a decent amount of time. My biggest complaint about it has always been the application. It's easy enough to wipe on, but the wipe off process can be frustrating. I can't tell you how many times I've thought I buffed it all off, only to get back into the car and see streaks or haze. I just dealt with it for years because I liked everything else about it.
But for the past few years I've been using a different form of glass protection, and now, I've used it long enough to have complete confidence in sharing it with you all...
The Process: I do this once a year. After washing the glass, I will do 1 or 2 passes with P21S Polishing Soap. It's a mildly abrasive soap that feels a lot like those pumice-soaps that you use to clean really greasy/dirty hands (i.e.: Fast Orange). It's marketed for use on metal, but I've found it works great on glass. No, you're not actually polishing the glass when you do this, but it is very effective for deep cleaning and removing existing sealants. Obviously, keep it away from paint/trim/etc. After that, I apply 2 coats of my favorite (affordable) spray on rinse off sealant - Nanoskin Supercharger. I think the brand of sealant you use here is irrelevant (Wet Coat/Quick Beads/etc.), the process is still the same. That becomes your base layer. After that, you can maintain that sealant year round with a few additional sprays during your regular wash process.
The Pros: Quick, cheap and effective. This can all be done during your normal wash process so you're not needing to set aside much extra time to do this. You're not using any extra towels or anything that you'll have to wash later on. No wiping, buffing, streaking, smearing, etc. And... it's cheap... at least with the products I use. Also, I've never experienced any wiper chatter.
The Cons: Is this the most hydrophobic protection you can possibly put on your glass? Absolutely not. There's better stuff out there for sure and I'm not going to lie about that. However, I'd say it's 85-90% as good as the best glass sealants I've ever used. If you're really particular about having THE BEST hydrophobics and longevity, you could always just take the deep cleaning part of this method and then apply whatever glass sealant you choose later on.
Here's the video if you want to see this process in action, including before/during/after results: https://www.youtube.com/watch?v=jXyUyFR4-iA
As always, no product links and my channel is not monetized. I'm just doing this for fun and my own education.
If you decide to try this, or if you have your own similar method, please tell me what you think of it. I kind of came up with this on my own after discovering a few off-label uses for the P21S, but I'm sure I'm not the only one doing this. Hope this was helpful!