I wanted to try to create custom cut foam inserts for shipping products so I picked up some closed cell and EVA foams for some tests. The closed cell foam (black) is a seat cushion and the EVA foam (gray) is an exercise mat.
I experimented with a compression bit, downward spiral, up spiral bit and engraving bit. Probably not a surprise that the compression and downward spiral bits performed the best. In the EVA foam the cut quality was amazing and the engraving samples also came out super crisp. In the closed cell foam, hard to tell in the video, the climb cut was actually really nice but the pockets were pretty bad. I think the key is going to be smaller step overs and slower feeds.

Links to the tools I used.
Downspiral Carbide Straight Bit 1/4" D https://amzn.to/2GivXyO
Amana Tool 46350K Compression Spiral 1/4" D https://amzn.to/2IsHHC9
SGS 30446 3 2 Flute Square End Mill 1/4" D https://amzn.to/2Uq3cVY
Amana Tool RCK361 Solid Carbide Insert 30 Deg x 0.010 https://amzn.to/2UoA29t
Amana Tool RC1075 CNC InGroove Insert Engraving Tool Body 1/4 Inch SHK x 21/2 Inch Long https://amzn.to/2Dh2mF8
DEWALT DWP611 1.25 HP Max Torque Variable Speed Compact Router with Dual LEDs https://amzn.to/2Dkoyyh