They've had some inconsistencies in their production runs, which has lead to various runs having more (or less) recalls. I believe there was one bad run specifically, though those boats were all in Europe. I forget what it was pertaining. Possibly the cooling process?
I know the cooling process is one of the big differences between the Blisstick production and Waka's. The roto mold is the same (as far as the hull anyway- major improvements are in places like the grab loops), though due to differences in cooling the rocker is a bit different. I find the Waka a far faster and less turny boat than the Blisstick, which I like (having also had the Blisstick).
They're still playing with more plastics. There are a few (okay, something like 8 or 14) grey Waka boats out there that are prototypes of a different plastic. There were conversations around the fire of going to blow molding. The grey boats are far stiffer, and a little heavier, so it handles a bit differently.
I've picked up a couple of Waka Tunas (one in the USA through Evan, and one in Norway). Quality appears to be similar. I found the one I bought in the USA seems to have worn a little more over far fewer paddling days. I did more rock slides by far in Norway, though I do wonder if I simply paddled more abusive runs/rock types in the USA? Uncertain.
Still, super solid boat. Front half and back half have different design characteristics regarding edging/chine, though it is definitely a boat that needs to be driven. It's awesome to lock onto a rail and feel like I'm paddling a slalom boat into an eddy at speed. The rails engage around where I'm sitting/under the seat. The front half the boat is a bit more forgiving. Adds another variable to how to paddle the boat.
I know the factory was shut down for a while as Sam had to get some stuff in order (back in August?). I haven't been following if they're back up and running. My guess is yes, since that was a while ago now.
Outfitting is alright, though I find the backband to be worthless. Basically, go look inside a Blisstick, and it's the same outfititng. A lot of the kiwi boys were throwing in a Zet backband and loved it. I've been trying to get one or two of those if anyone has a spare [Zet Backband] laying around... Also, elevating the seat ¼" or so improves the handling a bit.
A large percentage of my paddling is multi-day stuff with a loaded boat. One of the things I love about the Waka Tuna is how consistent this boat is from when it's loaded to when it isn't loaded. In that regard, it's the best boat I've paddled. That being said, I've found other boats easier to physically load the stern in the morning. About average in that regard.
Due to the hull design, as David Spiegel stated above, it's not as forgiving of a boat as a completely rounded creeker. Because of this, and that the boat really needs to be driven, I wouldn't recommend it to newer paddlers.
I also paddled the Zet Raptor, and it didn't work for me, so my paddling preferences my simply be similar to Mr. Spiegel's.
One of the guys I paddled w/ in Norway was probably 200+ lbs, and he was too heavy for the Tuna. It did OK, though he felt out of control and was going to sell his when he got home to the UK.