nightshard is 100% right, wattage is just the power being given to the coil, nothing more. It's the coils themselves that are the driving force for flavor/vapor production. I have a 1.11Ω coil that gives a flavorful and rich vape superior to the old premade coil tanks I used to use (smaller cloud than my TFV4 but denser and more flavorful by far). I run that at 35-40w. Likewise i have a .08Ω coil I run on a mech giving me 150w+ and it's not all that much different (slightly bigger clouds which makes sense since it has much longer coils, more surface area.
Anyways, If you want something awesome, go with an RTA, but you need good coils to make it better. Lots of places to get them, just stay away from the factory made 26g/32g clapton crap, it's not good. Check out something like Purecoils.com or hit up
@raymo2u to get some custom made coils that will last you a couple months (rewicking every few days though).
As for suggestions, Boreas is probably the best out there right now. However it is large and it makes it not a hands down favorite of mine (easily up there), my other favorite is the Diablo (clones but I use 2 of them now and love them). The Griffin also comes to mind as a good option, bigger build deck than the Diablo but there are things I like about the Diablo (flavor seems better, and it's compact). If 25mm is acceptable for you go with the Boreas for sure. If it's not and you want plenty of build space The Griffin. If you want something tiny the Diablo is great, though if you're new to building it may be frustrating working with the small space.
At this point I wouldn't really suggest any premade coil tank other than the Crown or some Atlantis style (Any that use those coils). Mainly the Crown has proven it's value and it's damn cheap. TFV4 I think is better, but not worth the extra cost. And the Atlantis style things are great because you can pick up replacement coils literally anywhere any coil is sold. But, again I'd go with an RTA if you're looking to upgrade, otherwise it won't really get all that much better.