Not so good build quality wise. I broke the transparent part on the day of installing. Be careful with light hands.
Pouring the liquid inside is a PITA.
But still the best thing to start with. Economical and work which they're meant for.
You know, it's interesting that there's a thread about drop checker quality and longetivity. Drop checkers are simply a method of separating one section of fluid from within a tank. With that in mind, the very cheapest HK glass dc's (the ones that look like a "?") are clearly the most dependable. Anything that relies on a rubber O-ring will clearly have less of a future.
If you do want to use something a bit more "modern" (i.e., cheap plastic), then, yes, that works. The other "CO2 drop checker" you'll get from Amazon, which is several dollars less, will also work fine.
The suction cups are generally crap, and are the first casualties, followed by the O-rings. But, honestly, if they last at least a few months (which is all of them), they're worth the price. After that, you'll be less concerned about drop checker color, but if you really want to have a visual reminder, you can buy another for 7 or 8 bucks. Not a big deal.
In the grand scheme of "stuff you worry about the price versus longetivity of", drop checkers are pretty much at the bottom of the list.
I use one of those Hong Kong specials off eBay but I recommend getting them boxed before being sent coz I had to have them re sent out as our local postman decided they would shove the parcel in the mail box and shatter the 2 I originally ordered
Apart from that they look pretty nice once in the tank