Back again on this topic: Heavengifts.com was so kind to send over the new OBS Engine SUB (prebuilt coils) to take a look at. While the tank itself has all the characteristics from the RTA brother, the included notch coils were unvapeable as stated earlier here.
After contacting heavengifts.com they confirmed that there are some problems with the preproduction coils and promised to send over some new coils as soon as they’re available. Fast forward a few weeks: OBS switched from notch coils to clapton coils and it was a wise idea to do so. The off taste is gone completely, there is near to no break in on the coils and they vape fine at 70-80W. The 0.3 ohm coils are specified to work between 50-100W and best at 65-85W which is pretty accurate, at least for 80VG juice.
Here is a comparison pic, the old (notch) coil on the left, the new (clapton) coil to the right:
The coils wick great but they are also on the wet side – I did not have any noticeable spitback but can image that you might run into troubles with higher PG juice because the coils might overwick and shoot some juice in your mouth. Even after letting the tank sit full for a few days, I did not get an unpleasent hit the first time – so no complaints from my side.
The rest of the party is pretty well known: Top side filling that can be a bit messy when closing it, top airflow that mutes the flavor a bit but the OBS version is for me still the best out there (for the Sub and RTA), 25mm diameter or 23mm in the mini version, 5.3 or 3.5ml fill volume.
If you are into subohm clearos and want a leak resistant cloud machine, take a look at this one. It is available for around $30 in silver and black and 25mm and 23mm at heavengifts.com – you can use coupon code AHG15 for 15% off!