which blade on this page is better, there are two pictured above? the top one or the lower one? i see a difference in their laser cuts.

I've used them both and both have a lot of vibration. Cut cleanly, but you will get tear-out on hard materials. I can't cut red oak with out chipping at the out-feed side without an additional sacrificial backer to prevent it with any Dewalt blades I've tried.

Are there 2 blades in the package, it shows 2X

I don't know what package you looked at? But the 60 tooth saw blade that came with the package is only good for rough cuts. I changed to a 90 or 100 tooth blade for fine cuts. Nice saw, just take it slow.

How does the 80 tooth work on oak? I had problems with other 80's burning and had to go 60

Hi Daniel: I used that blade before on my Dewalt table saw and it worked well for quite a while. Most cuts were rips with the grain, but to avoid burning I would push the stock through a little faster. Recently, I upgraded to the 3219 (https://www.amazon.com/gp/product/B003R7LBPG/ref=od_aui_detailpages00?ie=UTF8&psc=1), which works much better. It's priced more, but you get what you pay for. It cuts through my red-oak 1/2" panels and 3/4" stock like butter. There may always be some burn if you slow the push or stop, but that can be sanded off. Good luck.

Is the a good blade for MDF?

If you cut slow it's a good blade. If your concerned about chipping run a tape over the cut to be made. Remember: MDF contains VOCs (eg. urea-formaldehyde) so care needs to be taken while cutting and sanding to avoid inhalation of the particles.