|(Left to Right) SRb, SRc, UCR411a|
For some time, you either had to choose between the convenience of the slightly smaller (About double the efficiency) SR series or the reliability of the UCR411a. In 2016, Lectrosonics has released a newer version of the SR series, the SRc, which also features the front end filter that makes the 411a so great and add on the fact that the SRc is also wideband (about 76 mHz tuning range or 3 blocks).
I currently own each of the 3 so I decided to A/B/C compare them at my home in Brooklyn, NY. Below is the recording. You can download this, however, it will only be a 2 track stereo mix down. In this recording, the SRb is panned LEFT, the SRc is panned RIGHT and the UCR411a is center panned.
I did not notice huge differences between the 3 units. The SRc and UCR411a did seem to consistently produce a slightly cleaner signal than the SRb though. It's hard for me to say the SRc was better than the 411a, especially since it is my understanding that they should perform the same, but the worst RF hit came on the 411a and during the worst RF moment of this recording, the SRc seemed noticeably cleaner than the other 2 receivers, albeit, not perfect.
Technically speaking, the UCR411a still should outperform the SRc as it "still has a narrower front-end passband (11 MHz) vs. 20 MHz in the SRc and the 411A has a higher IP3 of +8 dBM while it is 0 dBM for the SRc. So no, I wouldn't say the 411A is obsolete, other than in size and weight." ~ Karl Winkler, Lectrosonics
Make your own judgements, but in my limited time using the SRc WITH the SRb and UCR411a, I am not worried about the wider front-end passband in the SRc especially since it's wideband and being able to find a clear open frequency is much more important than powering through a busy frequency.