Software won’t really matter once the MXM module comes out though it will probably cost you around $100 to control Vectras via Apex. So it really comes down to hardware and support.
I personally absolutely hate the 6-pin molex connector they use for 1-Link. I’ve broken a couple because it is a pain to take out. So, if I was using a cor15/20, I would use a power brick instead. Granted you don’t need to pull it out often, but when the time does come, it’s super annoying. I always have to use a flathead screwdriver to push the latch down. And most of the time, the eb832 is in a crappy position to be pulling it out.
I haven’t had an issue with any of the S2/M2/L2 pumps I had over multiple years of use. The S1/M1/L1 did have that thermal issue melting the plastic shaft where the impeller goes, but that issue was fixed in the second gen (S2/M2/L2).
My experience with Neptune and Ecotech support have been great actually. I’ve been able to get replacements pretty quick and reliably when a problem has arisen.