The first set I ever started collecting way back in 1981 was the Red Back set and it's one of my favorites. You can find nice conditioned raw Red Backs with ease, the Blue Backs not so much. While the blues are available prices are often high and it's much harder to find them in nice condition. I believe there were two and possibly even three Red Back print runs vs a single blue back run. While some blues were found along with hoards of reds in the late 80's, there were many, many more red backs involved. Doubles packs can still be found, although they are going up in price.
There are two types of Red Backs, cream/tan stock and brilliant white stock. The latter is much more attractive as the cards printed on the better stock have stayed white and have killer gloss. The Zernial (Philly) and Holmes (Hartford) variations are on the white stock whiles Zernial (Chicago) and Holmes (Boston) are found on the cream version. The difference between the two card stocks is obvious once you see them side by side. Blue Backs only came on the white stock.
The Doubles packs were a 1952 reissue without candy and contained primarily but not exclusively red backs. These packs likely sold off some returns from the previous year.
Here is an interesting couple of Red Backs with Team card backs that I got last year:
