w/o intentionally hijacking, Bruce, the "recommendation" may have been mine.
I own a SDC23. It came with the truck and I have had issues with it cutting out in extremely cold weather. I phoned Samlex, I said I was in a position to fix it if they would be so kind as to send me the circuit diagram. They were very helpful, sent circuit diagram, calibration instructions but my rig fell to pieces before I got a chance to repair it. (BTW, the issue was with the potentiometers regulating the max current and/or voltage output.)
As you correctly state, there are other converters out there. Samlex is one of many and I do recognise that they are less expensive than others I have seen. The "recommendation" from one Canadian to another was to take a look at Samlex's (Canadian = no import duties) offerings as an example, no affiliation on my part. We can discuss the merits this evening if you wish.
Mszekely, 13.8V output is just fine for almost all automotive electronics. They are typically specificed to run from anywhere between 9V (e.g. airbag control modules) to >>14V. The advantage of 13.8V is that you will be able to charge 12V batteries from that if you so desire.
If you wish to lower your risk, buy an expensive, better known brand. If you still wish to pursue a Samlex purchase, look at their refurbished SDC23's, they go for CAD 80 or so. Pretty good price for a 20A converter by my books. I also make assumption that any design issues with the SDC23 (old converter) have been long addressed.
Apologies if you feel you may have been misled. Not intentional.