Tested my new MD4 out this morning for a bit;
Fresh 180g C-MD4
Fresh 178g C-MD3
Feel: The feel of the MD4 is very familiar for MD3 throwers and very comfortable in the hand. It has a slightly more blunted nose and a slightly angled wing (as opposed to the MD3s rounded wing) leading to a nice flat top. The bottom wing with micro bead feels identical in the hand to an MD3.
Flight: In still conditions thrown flat, the MD4 and MD3 flew very similar. Surprisingly so. The MD3 will get a little bit of flip up with a hyzer or flex when thrown flat and always ends with a moderate, but not strong fade. While the MD4 did not flip or turn, the LSS was nearly identical. RHBH, it would end about 10'-15' feet left of the MD3 on a 280'-300' throw because of the lack of lateral movement, but was not as overstable as I expected. It still throws with a very straight flight and moderate fade. This let my expectations down a tad, I must be honest. However, the positive side of the MD4 is it's ability to resist wind and resist flipping up on a hyzer release.
In about 10-15 mph headwind, the MD4 still held dead straight without wanting to turn over at all. It has decent glide, so it still bounces up and down quite a bit, but it's flight remained stable. One issue I have with MD3s is that when thrown with power on a hyzer, they easily flip flat and even with a high, hyzered release, will not carry left (RHBH) as far as I would like. The MD4 handled this shot much better. Releasing with about a 45 degree hyzer and throwing about 30' in the air, the MD4 would ride the hyzer line, not flipping flat, and get good lateral movement to the left to get around a corner. Again, with the good glide for a decently overstable disc, it carries that intermediate drive or approach that needs to get around an obstacle much better than any of my MD3s including glow runs.
While I would still love to see a Discmania mid that is really beefy (gaaatooooor) the MD4 is a nice addition. It flies similar to an MD3, but stands up to power throws and wind better. It feels more like an MD3X than a truly overstable mid, but I'm happy with it. I think I will still be trying out my Mortar and Gila for more lateral movement, but the MD4 is a welcome newcomer that can cover a few shots that the MD3 struggled with. We'll see in the future if a glow or metalflake run puts this more into the Mortar/Gator realm of overstability for the utility hyzer shots many players crave.
Cheers.