I had an interest in flip-up modular helmets as well. I was considering the HJC Symax because it is well priced, and it has good overall reviews. It has a removable inside liner for easy washing. However after looking at the HJC at my local bike shop, i realized that the quality is nowhere near even the cheapest Shoei helmet. The helmet rattles, squeeks, and just feels flimsy when you hold it. Dont get me wrong, you cant beat the price for a flip-up (~$180 online, i believe), but the quality is only so, so. All Shoeis, by comparison are vault-tight, and naturally you pay for the quality.
SInce I couldnt affort the $350+ Syncrotech, and didnt want to settle for a low quality HJC, i bought the new Shoei RF-1000, ~$240) and I dont regret it one bit. The quality and engineering behind all the Shoeis is simply outstanding!
I'm basically waiting for the flip-up helmet technology (or perhaps market) to catchup with regular full-face helmets, so that we have more purchasing options. The HJC has been out for a couple of years now, and I would like to see them put some R&D money into a new design. Until there's a good quality, decently priced flip-up I'll stick with what I have.