Depends on what your goal is and what you want to achieve. Even with OpenWrt, you cannot use these switches for routing, as the performance will be in the range of 20-30MBit/s. After all, you could run light services like a DHCP server on the switch.
The biggest advantages I see with OpenWrt is the unified configuration experience and the fact that you know what's running on your router.
AFAIK, the whole GS1900 series has the same features. If you look at the supported switches, you will see a lot of Zyxels there.
Again, please note that it is designed as a switch, not as a router. You will get OpenWrt UI along with routing features, but the performance for routing is very bad.
Btw, I couldn't find any reference to a GS1900-16 v3 on the ZyXEL website. That's strange, since they clearly indicate GS1900-24HP and GS1900-24HPv2.
Where did you find the indication of v3, on a label?
This might be a confusion due to the switch series supporting PoE+. You have the same in the user manual, saying things like
The Switch supports both the IEEE 802.3af Power over Ethernet (PoE) and IEEE 802.3at High Power over
Ethernet (PoE) standards.
This is obviously only true for models with PoE ports. I.e not the GS1900-16. I guess the ad is the same way. But I agree that it is misleading. Would be better if they didn't merge all these different models into the same ad with a shared spec like that.
As for the v3 thing - I believe that came up here earlier, possibly related to some other model. It seems the v2 and v3 suffixes exists on labels. Possibly related to software or other irrelevant differences? I donæt remember the conclusion. But ZyXEL don't change SoCs without changing model numbers, so you can be pretty sure a GS1900 is either supported or supportable by the OpenWrt realtek target.
ZyXEL keep a pretty good, and AFAIK complete, overview of all the hardware variants in the user manual. It lists only A1 and B1 variants of the -16. The visible difference is "reset" (A1) or "restore" (B1) buttons.
I'm very happy with my ZyXEL switches and routers.
I like developer friendly details like
the, already mentioned, consistent model numbering so you don't have to guess the internal hardware,
a console header usually (always?) mounted so you don't have to solder anything,
mostly complete and working (building) GPL dumps
It's not that it are any major differences compared to e.g Netgear, where you get none of the above. But those minor.things add up to ZyXEL just being a better choice.
The hardware quality is among the best for this equipment class IMHO. And the OEM firmware actually isn't as bad as much of the stuff other vendors throw into their products. All based on the same BSP/SDK of course, so I'm considering the vendor specific additions and fixes only.
One of my NR7101s is running OEM firmware since that's the reason I have it, and it works very well FWIW.
This came out a bit like a ZyXEL commercial.... But I do mean this stuff.
Should mention that I work for an ISP buying lots of ZyXEL CPEs. Which means that I have some interest in making ZyXEL equipment look good. But we do have our reasons for choosing ZyXEL, and it's not primarily price. The price could definitely be lower
I don't have as much experience as @bmork (advanced home user), but I ended up running my house on two GS1900s (GS1900-24HPv2 and GS1900-24E). I have tried:
Old Netgear GS724Tv2 - not comparable due to its age. It got the job done, but the web interface was pretty basic and the fan started to make noise quite soon. Sold it.
TP-Link T1600G-52PS - relatively expensive due to 48 PoE ports, unintuitive firmware. Never had a real problem, but TP-Link changes SDKs, firmware layout, partition layout, hardware ... all for the same model. Sold it, although I made an OpenWrt port.
D-Link DGS-1210-28MP - nice piece of hardware that I got for free, I don't use it actively. It's not easy to identify the chipset from the outside, as D-Link also changes SoCs between revisions.
ZyXEL GS1900-24HPv1 - sold it ultimately due to fans running always on full speed and only 64MB of RAM
I can recommend the small Netgears, like the GS308T and GS108Tv3. I have both of them and I'm very happy with their price/performance ratio. I don't know about 16 port models.
I would also recommend having a look at the second hand market, if that's an option for you. Where I live, the GS1900-24E can often be found for €50,- or even less.