I would like to know who makes the BEST kit of the German 88mm flak in 1/72nd scale when it comes to acuracy and detail?

Hasegawa does the 88mm Flak 18 and the 88mm Flak 36. The latter kit is the former kit with a new barrel. In other words, the Flak 36 kit includes the complete Flak 18 kit and contains a new barrel. Both are fine kits.

If you see the Airfix Flak 88 kit advertised as 1/72, it is just their old 1/76 scale Flak with a new scale attached. Not as nice as the Hasegawa kit and not the scale you asked for.

Planet Armor does a FAMO 18t half-track with an 88mm Flak mounted in the back. Most likely a nicer overall kit, but at least three times as much for this resin kit.

Check out this link for a review of the Hasegawa 88mm Flak 36 kit:

http://www.ontheway.us/reviews/Hasegawa/flak36review.htm

Also ARMO makes turned 1/72 barrels for both the Hasegawa kits and I just got them; they are quite nice.

Cheers,

Richard