I'd say the trailer is the most important part of a swim jig. Some paddle tails will give it more roll than others. Some trailers like a Rage Menace rigged vertically won't give the jig any roll at all (which I like in colder water). Craw-style trailers will help keep it higher in the water column.
As far as weight goes I mostly throw 1/4 oz and 3/8 oz. 1/4 oz is I'm fishing rather shallow. I'll sometimes bump it up to 1/2 oz if I wanna fish it deeper. 3/8 oz is probably the most common size people throw.
Colors...I fish black/blue a ton. I fish a lot of stained/dirty water. White works well, too. In clearer water I'll throw bluegill colors or green pumpkin. Those 3-4 colors, or a variations of those colors, are really all you need. Sometimes I'll dabble in fire craw and chartreuse colors...mostly in the spring.
As far as brands, Siebert's gets my vote. But I probably have 15 different brands. I also like 6th Sense, Greenfish Tackle, Satone, Strike King, Beast Coast, Dirty Jigs and Outcast Tackle. The Lethal Weapon IV comes thru grass really well. Oh, and I do like the Missile Baits Mini as well when I want a smaller profile.