I've had a chance to try out a few different D8 and D9 seltzers now, the latest of which are these 20mg D9 seltzers from Blitzd (D-Squared Worldwide). Though seltzers or drinks in general aren't usually the most cost effective option, especially if you have a high tolerance, I enjoy them because they are fun and convenient and I like how quickly and consistently the nano D9 they are made with hits.
Packaging - These come in a tall can like you find with most other seltzers and they have a few different flavors. The label and such is attractive and professional looking and has all the information you would expect on it. There's a sticker with a manufacture and expiration date as well as a QR code for labs.
Labs - The labs for these are from Bluebonnet Labs and show between 22 and 26mg of D9 depending on flavor, all slightly over what is advertised.
Flavor - These come in a few fruit flavors; lime, blood orange, and watermelon. These are true seltzers in the sense that there isn't any sweetening or calories. There is a little bit of caffeine added in, but it's a relatively small amount, about the same as a can of coke. The flavors are all pretty good, tasting like what you would imagine, but it course with no sweetener or anything there's that typical seltzer taste to them that some dislike. I don't mind it, but it's not my favorite either, I could kind of take or leave seltzers. If you like a typical unsweetened seltzer you will like these too.
Effects - Since these use nano D9 they hit quicker and a little stronger than typical edibles do. Dosed at 20mg each they are just about perfect for me, one can is enough to be fun without overdoing it. If you're new I would suggest starting with half a can or less just to be safe though. The added caffeine helps keep things from feeling too sedating and kind of evens out the tiring effects of the cannabis to make these slightly better for daytime use. Effects do indeed hit me pretty quickly, usually within 20 minutes or so. They feel maybe slightly stronger than a typical 20mg dose would be, but also tend to not last quite as long too, which could be seen as a positive or a negative depending on how you look at it. I get effects for probably at least two hours, but it's not going to last like six hours or more, which some edibles can do for me.
Conclusion - While there's nothing revolutionary about these particular seltzers they are solid enough, they taste fine and are dosed really nicely for me, and have been very consistent effects wise so far.