Definitely sad to see one of the old guard companies go, especially since they kept so much in the US.
I was never really a fan of theirs when brushless started to take over. The ROAR rule book was basically written around their then current product line keeping sensorless (and Castle) out of racing for awhile. But Novak didn't do all that much with that advantage. Everyone else went with computer interfaces and program cards while they stuck with a few drive profiles, less gimmicky but not as desired with less adjustability. Do you want one esc that can run in anything with a few adjustments or a more limited or even application specific esc (like Novak's crawler esc) that can't (or at least makes you think you can't) swap to another vehicle type? Castle blew up and Tekin came back from the dead because of these features and the motors to go along with them. Just look at the Tekin RX8, MMpro or MMX. They can run anything, brushed, brushless in sensored, sensorless or a hybrid mode, with any adjustment you'd ever want and now datalogging on the MMX. Honestly even Hobbywing has had Novak beat for awhile now when comparing an esc's capabilities.
Then there was the supposedly 1/8 scale HV system with a rotor way closer to 380 size. I think the lowest kv on them was 3000kv and they went up to 5000kv. The HV's were popular motors for the 4x4 SCT 2s guys though. A few years back Novak did release a much better 1/8 system. The esc is pretty kv limited though due to its slow switching speed. The kv ranges are ok for racing but not so much for the bashers and definitely not the speed run guys. Plus it came way late in the game, Castle and Tekin had long since established themselves in the 1/8 market with Hobbywing and the other cheap stuff coming on strong too.
I honestly hadn't given much thought to Novak at all in years. The last time I saw them in a magazine (can't remember when) was an ad for their crawler esc and nothing else. The only time I've seen them mentioned in the forums is for their 550 motors in reference to the guys who have to run a ROAR legal motor on 2s for 4x4 SCT. But that was always with a non Novak esc (usually a Tekin RX8) and even that convo has moved away from Novak's 550's towards the 4 pole 540's. Now that I do think about it I'm not really surprised. Still sad though as they were once a market leader and it would've been nice to see them come up with something to truly compete with the other brands in the market.