SAS is Southland Archery Supply, SWA is Southwest Archery. Two different companies. The Spyder and Spyder XL are marketed by Southwest Archery Supply which is based in California.
The Spyder is just a nicer version of the original Samick Sage. The Spyder XL is a longer version of the Spyder. The Spyder is a 62 inch bow, the Spyder XL is 64 inch bow.
I own both. The only thing I would do is order the toolless take down limb bolts, as the traditional allen key limb bolts are soft, inferior quality and prone to strip, even if you are careful. This happened to me, rendering my bow useless, The tool less limb bolt is the way to go.
Depending on your draw length either the SW archery Spyder and the Spyder XL will work well. If you are drawing past 29 inches, I would go with the XL, as the longer bow will be more comfortable to shoot. Both bows are tapped with AMO bushings for sights, quiver, stabilizer etc.
The SAS line of bows are also good quality, I dont own one, but a friend of mine does. I can only speak to the Southwest Archery Products. SWA has good customer service and a one year warranty if the bow is registered online within 30 days.
Most recurve and longbow makers only offer a one year warranty. Bodnik Archery offers a 30 year transferable warranty. They make really nice products, but they of course are way more money.
My SW archery bows shoot just as good as my Bodnik recurve. Love them all, SW archery products are really good for the money.
Most of the Samick Sage clones, are probably made but the same company in Korea and then just rebadged buy whichever company is marketing them.