I've been doing a ton of research to try and find the best (if there even is one) product to stain, seal, and resurface an old untreated deck with splinters, and some heavy duty cracks. I originally looked into Rustoleum Restore, and have seen nothing but nightmare stories of peeling and the class action suit going on. I did however hear they recalled the old formula and also added a primer to the process. I didn't know if anyone knew anything about this, or had more info on it. I'm also aware of how important the prep work (cleaning, drying, caulking/patching cracks and gaps, etc) is to getting whatever product I end up using to work.
I'm sure the only guaranteed way to resurface an old deck is to rip up and replace the boards, but that just isn't in the budget or time frame right now.
Look at Gulf Synthetics Deck Revive for a deck resurface stain that actually has good reviews.