Thanks for the input! I'm perfectly satisfied with the Novatac lights really in every way as an EDC light other than their size. This was true for the HDS I owned as well. For pocket carry in business casual attire they are just a hair larger than I find totally comfortable. The Ra lights bring a lot to the table and I expect would be equally satisfying, but their larger size more or less takes them out of the running - I'll stick with the Novatac...
I'm a bit worried about the Arc6. My last experience with Arc was a 4+ that was a bit of a love/hate relationship. I loved the form factor, design and the UI. As the great grandparent to the HDS/Novatac/Ra lights there was much to like. Mine however had one of the reknowned faulty switches and despite me tinkering, a lot, to get it to work I never could. By that point, Arc had gone out of business and I was stuck with a $200 piece of artwork. If I'd hung on to it long enough and had the crystal ball to know to do so I could have gotten a decent trade in credit towards an Arc6 but I sold it basically for salvage value years ago. The HDS was a huge step forward and my HDS and Novatac lights have been rock solid reliable - if not as aesthetically pleasing as the Arc4.
The Arc6 is a sexy light and since McGizmo seems fully committed to Titanium (and the related cost) I'll likely never own one of those. The Arc6 combines programming capabilities (which I see drawn towards) with the proven McGizmo piston drive and related body mechanics. I do worry a bit about the relative lack of buzz/input on the light around here - not a lot of track record to gauge the reliability (and I value reliability quite highly - one reason I've stuck with some of my basic lights for a long time). I also worry that the efficiency is not quite as good as I'd like even in the center of the bell curve (levels 3,4,5) - I can accept that at the outer limits of level 7 efficiency is more or less gone out the window and you're just pushing the envelope hard for a short time. And lastly, well, I worry a bit about the long term viability of the company - I've gotten stuck in the past and once bitten twice shy (and FWIW the complete silence from Novatac regarding any new products and reports of reduced customer service...).