As you will be well aware (and maybe seen the beta versions) Twinmotion is releasing an Unreal based realtime renderer for Revit & Archicad. Initial impression of this system is that it will be one of the best out there for full function (animation/materials/objects etc) real time rendering but it will no doubt come at a significant cost. Looking at their current pricing I would suggest they will be more like $200US/mth which is more than achievable for big firms & big jobs but not something I am going to be jumping at to showcase my everyday residential designs. If they pitch it at $100US a month it could entice me & other archicad users away from Enscape, I realize that is double the price but per month an extra hr of work to have the extra features is an easy sell.
The point I am trying to make is that you shouldn't spend all your development time/$ on options within enscape please just stick to a straight render that works like you currently have it and you will capture a segment of the market that twinmotion will not be competing in. Simple proxies for sound/vegetation/lighting is all that is required then let all the work be done in the main software beit revit/sketchup or archicad.
On the Archicad point. Twinmotion is being released with the 1 click syncro add-on built into Archicad. As an Archicad user I currently output through sketchup to Enscape which looks fine but when meeting with clients it makes 'changes on the go' not possible. This will be a big aspect in any decision between the two options. The sooner you have an Archicad add-on the more likely you will capture those that don't want to fork out big $$ for the fully featured twin motion & I would suggest that would be a good chunk of Archicad users.
What you are offering with Enscape is simplicity. Don't overdo the options just do what you do and do it well at a sharp price. You will still lose out to those customers who want the bells and whisles but at least you haven't spent big $$ trying to hold onto them.
I will be getting my hands on the Twinmotion system as soon as I can but if they price it to suit the commercial market it will be an easy decision to stay with Enscape. (as long as an Archicad add-on is only months away!!)