I've tried them. I like them both. My impression is the Colossus is a barely sweet
juice that is a natural mild vanilla flavor with a little custardy eggy note. Improves some with a steep. I like it but it's very mild and kind of 'dry' to me. Good if you don't want hardly any sweetness.
The Poseidon is a mildly sweet fresh melon with some added fruits, it's not an in your face fruity but a more refreshing fruity.
Those are my takes on it but yours may be different.
I think they only have two flavors because they are pretty new. Lots of vendors work hard to make a few things well, and then slowly add more. According to their facebook page "Athena, our new green apple flavor will be released soon"
Right now you get 40% off (code is on their front page)
I tried them on a protank 2.
There are
reviews of each on their site and also a couple more here:
E-Liquid Review #10: Colossus & Poseidon from Cyclops Vapor - YouTube
ZB Rating | Colossus by Cyclops Vapor