SR3500 vs. SR3100
 

Which is the better choice? They are the same price, but I have been looking at their product pages and besides the SR3500 being a slight bit smaller I can't seem to find any difference.

Do you have a DX3R? If not, the SR3100 won't work for you. The SR3100 is DSM2 and the SR3500 is standard DSM. Personally, I like the SR3500's as they are super tiny.

Sr3500 = dsm
sr3100 = dsm2

Probably just the case.

and the mini size.

I never could tell the difference between a 3100, 3500, or a 3000 besides the extra channel and mini size.

I have a DX3R. I think I like the 3500 since it is so small also. I'll most likely go with it. The DSM2 is suppose to have lower latency, but the 3500 says it has the same latency as the pro models. Does pro model mean DSM2?

No, the Pro is not the same as the DSM2. I can't tell you what the difference is, but I know that even when using a Pro Tx module, you cannot use a DSM2 Rx.

Also, look around, you'll find the SR3500's just a tad bit cheaper than the SR3100's.

I haven't been able to notice the "latency lag" at all.
Then again, I don't race...

I'll see what I can find.

If you have a DX3R and don't need a micro receiver I recommend the SR3100. The latency isn't necessarily a noticeable benefit but I always get more then twice the distance out of my 3100 then any DSM receiver I have used