Yes, I would say it’s definitely worth testing. Obviously, a mattress that suits your needs may also be beneficial (perhaps more so), and I know everyone’s own unique circumstances will provide different results, but I’m happy to share my personal experience.
I knew, after only 15 minutes of testing at the store (I sleep mostly on my back, although occasionally on my side) that it would be a worthwhile purchase. As Phoenix said, just a slight elevation of the head and foot was enough to take pressure off of my SI Joint. I can only imagine what result adding the proper mattress might achieve, but in the 3 months I’ve owned my adjustable bed, my SI Joint has gone from excruciating (and debilitating) to most often just a nuisance.
It has also helped two other medical conditions somewhat. I have worn a cast, boot, or brace - most recently, an Arizona (AFO) brace - on my right ankle for the last 15 years. The Arizona brace has evened out my gait, but the damage to my SI Joint was already done. (A Simmons mattress - replaced 3 times under warranty - definitely hasn’t helped). I need to keep my ankle elevated at night to keep the swelling down, which was always such a pain with pillows. I also have a (mild) case of sleep apnea, and although I diligently try to wear a CPAP machine at night, it’s always off by the time I waken. Elevating my head helps with the sleep apnea as well (also a pain with pillows)
One word of caution: I would test mattresses separately from the adjustable bases. Almost any mattress feels more comfortable on an adjustable base!! Also, I was on a very limited budget and didn’t think I could possibly afford an adjustable base. However, since my husband passed away several years ago, and I also now sleep alone, I was able to downsize to a queen. Still, I couldn’t find a base less than around $1,100 locally (before tax and delivery) However, I was able to find a very basic (Serta-branded) Leggett & Platt model on US-Mattress.com for $699 including tax and white-glove setup. Both Sears and Mattress Firm include adjustable bases in their price-matching policies (not that I would recommend buying a mattress from either place, based on what I now know), so I was able to get a queen base for $629, with tax & delivery included, delivered the next day (sometimes Amazon will also have an L&P at around $699 as well - although it may be branded by another company) Be aware, though, that bases are not typically returnable under a trial period, and if they are, you will probably be responsible for the cost to return it.
Mine is a very basic model with none of the bells and whistles (Serta Motion Essentials II), and although USB/AC outlets, built-in Bluetooth, nightlights, massage (basically vibrations), and a backlit wireless remote w/presets might be nice, mine has a very functional wired remote that does everything I need sufficiently. Plus, I’m the type that’s always digging through the blankets looking for the TV remote, so a wired remote is actually a benefit for me, lol.
Good luck in your search for a mattress. I, too, am hoping to find a new mattress that will continue to help alleviate my SI Joint pain. I’d love to purchase an all-latex model, but am not sure my budget will allow it at this time; however, I have learned so much about what to look for in a mattress from reading the detailed articles and forum posts at this site that I’m certain I will find something much better than what I had, at any budget level.