My 2cts - your mileage may vary:
The NI implementations of CA (client and server) were indeed getting better over time, but they started at a very low level of compatibility.
Their newest versions are pretty much working (at least for scalars), but - especially for their CA server - you are
always
in for some surprises, and your clients might need special configuration when talking to an NI Channel Access server.
I can just underline what Gabriel wrote: In my experience (which is obviously biased as I was working at BESSY for a long time), CALab is the most reliable, robust and stable CA client for LabVIEW.
(Doesn't just look better - it works better, too!)
Cheers,
~Ralph