I've been using mine for around 8-10 hours a day on average, for 4 weeks now and I agree with most of your observations.
I've been using my ADV tobacco blend juice in mine, all day every day with the airflow fully open on top of a Squid Industries dual 20700 TAC21 mod at 80 watts. However I don't find the vape or the tank itself gets hot at all and for me its a very pleasant warmish vape. Touching the outside of the tank even after successive long chain vape hits at 80W finds the tank feels warmish but definitely not hot (to me). The warmth/heat level of the vape that people prefer is probably very subjective though and would vary significantly among vapers (just like flavors do).
Mine registers 0.23 ohms on the TAC21 and hasn't fluctuated from that once over 4 weeks use.
You're spot on about the fill port. The tips on my 100ml chunky gorilla bottles are just a touch bit too thick and the tip sits 'on' the fill port cut out of the tank rather than being able to slip 'inside' it. Joyetech could've made that kidney shaped fill port just a tad wider. I can still fill it relatively easily but I have to be careful and deliberate when doing so rather than being able to just stick the tip in the hole and squeeze. A minor issue really though.
What's amazed me most about this RTA is that the quality of the vape I'm getting (both flavor & vape production) hasn't changed one bit in the slightest over the 4 weeks of heavy use so far. This is despite the fact I'm a chain vaper and I refill the tank several times a day (read: at least 4 or 5 times a day).
As a result, I haven't had to change the cotton or dry burn the heating plates yet (despite this nagging feeling that I should have done so by now). I'm going to continue to hold off doing so until the vape either starts to suffer from a loss of flavor or starts to taste funky or I start getting dry hits (which I haven't had a single one of as yet) or something else forces me to do so.
I'm really interested to see just how long it will continue to perform well before I need to dry burn the plates and change the cotton. It could be due to the fact that its a tobacco blend juice with very little sugary type ingredients in it that would lead to premature gunking up of the heating plates. But nonetheless - 4 weeks solid chain vaping each and every day with no loss of flavor, vape production or dry hits, and not having yet had to change the cotton or dry burn the heating plates makes it a HUGE winner in my books (well - for my vaping style & preferences anyway).
A winner for me so much that I ordered some more of them on the weekend. I'm going to specifically use one of them with my favorite dessert juice that I revert to most evenings and naturally it does have reasonable sugary ingredients in its make up, so will be interesting to see how long the Riftcore can handle heavily sweetened juices before requiring a cotton change and dry burn.
Thanks for the kind words Nicaholic , I did just bump it back up to the full available 75 watts and open up the airflow wide open and it is much cooler than before but personally prefer the airflow 1/2 way so 65 watts it is for me
I experimented with closing off the airflow myself a couple of weeks ago. I tried it 1/2 and 2/3'rds closed off for a day or two each and at different wattage settings between 55w & 95w. You're correct that it does make a difference to the warmth of the vape. i.e. - its warmer with less air flow and cooler with it fully open and as you have experienced this also varies dependent on the wattage being applied as well.
The thing I found though with closing off the airflow to halfway or 2/3'rds was that it caused a condensation sort of build up of juice situation which collected around the base of the Riftcore and of course seeped underneath the tank pooling on the top of my TAC21 and around the 510 connection. This meant that I had to take the tank off the mod at least a few times a day and wipe the excess juice from the bottom of the Riftcore and the top of the TAC21. That became old very quickly.
I figured out through trial and error that it was happening because of my vaping style and it wasn't really a result of any particular fault with the Riftcore itself per se. By closing down the airflow, combined with my chain vaping style and combined with the dense juice laden plumes of vapor I was producing, the problem lay in my habit of purging the Riftcore prior to every vape draw that I take.
So what was happening was that I was forcing heavily juice/moisture laden vapor out through the partly closed off airflow prior to each vape I took and just like what happens to your bathroom walls from the steam created when you take a hot shower, the vape moisture was collecting around the 3 airflow slot and then gravity was doing its thing and the juice formed on the bottom sides of the tank from the moisture laden vapor began pooling on the bottom of the tank and then slowly sliding down onto the TAC21 where it began to pool up until I wiped it clean.
Since opening the airflow up fully this hasn't happened since but as you correctly point out, opening up the airflow fully does cool the vape down, so I upped the watts to 80 and have been a happy camper since.