The SPS and ADL are the same gun. The SPS has a floorplate and the ADL has a blind magazine. You generally get the ADL for a little less money and having the floorplate is not a huge deal to me. Espeically on Remigtons. They have pretty cheesey bottom metal anyway, so I'd just as soon save a few bucks and get the ADL. The savings can go towards a better scope. The 783 is unproven, and I'm not willing to be a product tester. The 700 isn't my favorite design, but it is a good one.
If you ever plan to upgrade to a better quality stock any BLD stock design will fit the SPS and there are more options avalable, especially on cheaper aftermarket stocks. But I cannot see replacing a cheap factory stock with a cheap aftermarket stock. All of the quality aftermarket stocks are available in BDL and ADL.