Every once in awhile I decide to try something new. In the Tanks with the Bottom Air Flow I had standardized on the Smok TFV8 with the Sextuple Coils. Then I decided to try the RBA that came with it and I like it a lot. But I decided to try a different technology with the Air feeding from the top. I researched and found mostly good reviews and some not so good about the OBS Engine. I was attracted by a few things. 1. Very Easy to Disassemble, just screw the bottom off 2. Wide RBA Deck 3. Super Easy Refilling. BTW The swivel head on the Smok TFV8 is often hard to swivel and locks into place. Also the fill hole is pretty small. 4. A different technology. Air entering from the top to aerate the coils. 5. It holds a lot of juice 5.2ml and it's squat not tall. So my OBS Engine arrived today and I opened her up and was very pleased.First I noticed Professional packaging along with a readable manual with diagrams. I was really pleased that dissasmbly was as easy speasy as in the videos. Sometimes the littlest things can make a difference. Instead of coming with a cumbersome flimsy L shaped hex, it came with an actual screwdriver with a plastic handle. This was much easier to use than the hex that came with the TFV8. Another thought on my second rebuilding of the TFV8 while I was waiting for this to come in the deck broke pulled out at the center. Partially my fault I didn't have a nail clippers and my wire cutter was blunt so I was bending thick clapton wires around. But anyway the TFV8 only lasted two rebuilds. Luckily it's only the RBA deck that broke so I can still use assembled heads. I used premade 316L Stainless Steel Triple Core Fused Clapton Coils 28gx3/36g x10pcs (3mm/6 wrap). Sorry but I'm just too lazy to make my own when I can buy them for around 2 dollars a pair. Also my coils last for months because I use a homemade clear Juice so not much gunking. The biggest decision was how to tuck in the cotton. One reviewer tucks in the cotton under the coils and doesn't actually put the cotton into the holes. Others have said that they just have the cotton lightly covering the holes. Me I decided to play it safe? and stuffed the cotton down the holes while making sure it wasn't super tight. Well my first vape or two was a little sputtery but since then it's been perfect although I hear a crackling. Not sure if it's because my cotton is inconsistent or if the coil and cotton just need breaking in or heavens forbid it's flooding or too dry. I was vaping at only 58 watts . Oh boy I just moved it up to 68 watts and the vape is sublime. When I chain vaped it a little the crackling went away. Any opinions on this? Sounds like a flooding issue? Strangely enough when I was dry firing both coils where heating up but the resistance was at .34 after I filled with cotton I have a resistance of .14 which is spot on with what the manufacturer represented. " 3mm / 6 wrap (Approx 0.3 ohm per coil, 0.15 ohm in dual)3mm" It's just strange because I saw both coils heating up yet the resistance was equal to a single coil. By the way I'm Mr Two Thumbs so if I can build this RBA probably anyone can. Now it's time to experiment with variable voltage. Hurray. My final thoughts is that this RBA is a contender.