I received my Kwark Navy suit a couple of weeks ago. I ordered mtm, through the techduikshop.nl and that was quite bad experience with long delays, emails without replies, misspelled address etc. But finally I got a suit, mtm and the fit is great.
Kwark Navy is a really simple fleece undersuit. It feels warm for it weight but it is not very thick. The suit is absolutely a pleasure to dive. Doesn't restrict movement at all, and air circulates extremely quickly in the drysuit.
There is no way it could be equivalent to Santi BZ400X or Weezle extreme in warmth. But that said, it is quite warm and I dove it 75 minutes with 9 C bottom temp (warmer during deco). Material also seems to be reasonably warm also when wet after a minor neck seal leak.
Overall, I like the Navy but I doubt it will be warm enough for most of my diving.
The suit is a simple fleece overall, so there is nothing unique in it if compared to other similar products like Rofos Artic.
Thanks for the mini-review!
On your 75 minute dive, what base layer and what kind of drysuit (trilam or neoprene) were you wearing?