So I got my GDMods MD-01 in the mail!
(Review I'd looked at)
Overall, very nice! I'm coming from an old Siren V2 and this is both slightly more simple, and also slightly more annoying.
A very versatile device as it comes with two airflow systems, and two juice control systems. These can be swapped between each other for even more options. I went with the MTL setup.
Building on the deck is great, performance and flavour also great. No top-fill though which the siren V2 does very well. Additionally, to get the atomizer back on the deck you have to line some things up and really force it. Might get easier over time as the O-rings get juiced up but the markings are miniscule and I find myself squinting. Also squinting to re-align the airholes as I really have to tug on things when rebuilding. However, bottom fill isn't really an issue as it's 5.5 ml and it's a simple twist off.
Overall I'd say it's a great addition to the two others I use (siren v2 and brunhilde). Flavour is amazing and the draw is smooth. However my siren v2 is pretty bullet-proof for when on the go / refilling on the fly / not having airflow change on me on the fly. But it's a real keeper for at-home use!