I have been looking around trying to understand the differences between the following Spektrum receivers: SR2000, SRS4210, SR410/415

I see they talk about a 5.5 ms frame rate for the SR2000 but they dont say what it is for the SRS4210. Does anybody know?

Then I noticed I could get the SR410 significantly cheaper than the SRS4210. Does anybody know what if any performance differences there are between the SRS4210 and the SR410? I don't want AVC which seems to be the only documented difference I can find.

Thanks.