New to DE

Hey guys!

I am a returning WH40k player, been about 15 years since I played last. I brought quite a bit of DE because I love the way the DE army looks and they are the most mobile force in the game or so I thought. I am putting my army together and painting them atm.. I have a few questions about the DE and hope some of the more experienced players can help me.
First of all, why are our Pain Engines (dreads) and Flyers in the Heavy section?? All the other codexes I have look at have dreadnoughts in Troop (or was it Elite) and their Flyers are in Fast Attack. It really limits the choices we have. I would love to field some Pain Engines, just because they look sweet, but really cant justify it because our other Heavy choices fits into the army much better. Bugger...
Now I hear that Eldar are the new super mobile army?? They got Battle Focus or something, I thought everyone could move and shoot?? Or is it just move and snapshot? Dont tell me the sissy Eldar are most mobile now..

Are DE still competitive? With the new rules, heard that more weapons now ignore Feel No Pain and we lost some movement in assault I think it was. Tau looks like a serious pain in the a.. now.

Thanks and love the forum
goofydk

Our Heavy Support layout is a huge pain.
My understanding is Eldar can move, shoot and run.

Deldar are still competitive, they are just complicated.
I do very well with 8 venoms.

Hmm sounds like I need to buy more venoms...

Cant other races move and shoot? (yes I have read the rulebook but it was a very very long time ago (last year.. )..) I find that a bit odd

Dark Eldar are still more mobile than Eldar.

Sure the new Eldar "battle focus ability" lets their infantry move shoot move, but the catch is you have to be on foot to use it (so you are are sacrificing speed in order to use it). Their shuriken weapons also have inherently shorter range.

Dark eldar still have open topped vehicles (shoot and assault out of transports, ravagers and reavers (can do loads of damage on the move).

Eldar can make one of the most annoying most resilient armour walls around. What they cant do is assault. Dark eldar remain one of, if not the premier assault delivery armies thanks to open topped fast skimmer transports and beast packs. We are also anethema to all their big uglies. Even better DE/Eldar are battle bros so if you want some extra anti tank or what have you then ally for it.