I am skeptical of the two feeders mentioned due to the strange looking support system they both have. The normal production feeders have a threaded hand wheel arrangement. See this link: http://www.toolbarn.com/product/delta/36-850
Delta 34-850: 1/4 hp 3 wheel 4 speed stock feeder
I have a similar stock feeder to the 34-850, it seems like mine is discontinued, see below:
Delta 34-985: 1/6 hp 3 wheel 4 speed stock feeder
Here's a grizzly version that looks good: http://www.grizzly.com/products/1-4-HP-Power-Feeder/G4176
The support system on the feeders you mention may be okay, I just suggest talking to someone who has one first. I like the hand wheel adjustment where you can lower the machine down when feeding to get the right amount of pressure. When I got mine it was the smallest type of production feeder from Delta. It worked fine for me for feeding many hundreds of hex sticks through my shaper. It also did a fine job for shaping raised panel doors for my kitchen cabinets. Looks like the hand wheel type of feeders are a bit more expensive.