As a general rule, most USB/Serial devices use one of two manufacturers chipsets and a reference design. The chipset manufacturers are Prolific and FTDI. So comparability wise, one manufacturers hardware based on a particular chipset is likely to be identical to another manufacturers using same chipset.

Both manufacturers have problems with their chipsets in different circumstances, but FTDI are generally slightly better in this respect and some early Prolific chipsets have dropped off the compatibility list with regard to OSX compatibility - my trusty prolific adaptor does not work with my Mac, although it works with Windows (certainly until W7) and Raspberry Pi.

The Keyspan recommendation was made many moons ago and the chipset that it was based on is probably long retired. However, Meridian do use FTDI based chipsets for their G series maintenance ports.

However, the biggest benefit of some of the FTDI chipsets is the ability to retain COM port assignment, meaning that once a com port is assigned for the device, it should not change.

I've used a different StarTech device than Duncs recommends and can vouch for their reliability - I ran it over 1000m via a RS485 adaptor continuously for several weeks without issue. The one that I used was FTDI based and had fixed COM port assignment so I would say that Duncs version is a pretty good choice too.

I'm not criticising the Prolific chipset, but they sometimes take a few tweaks in the Meridian config and Flash uploader to get them to work. These are the throttle and interval mentioned in the Wiki.

However, if I was buying again, I would check that it is based on FTDI chipset.

Meridian owner since 1992
Prime & PSU, Focal Elear headphones, Roon (ROCK 8Gi5 NUC), Explorer 1 & 2, F80. 200/203, various Sonos (via Roon).