I spent some time last night getting everything set up on the new card, copying old files over from my half-dozen other VMUs, and I have some initial thoughts.
First off, the screen is bright and clear, and initial battery life seems good, plus the ability to charge the VM2 through the controller itself is a godsend. And the ability to just keep all your saves on a single card without having to bust out another controller just to have a VMU screen and a rumble pack and the 4x memory card where all your saves are ACTUALLY stored is super convenient. That's what I've wanted ever since I first got my Dreamcast!
My biggest complaint so far is that the screen isn't the correct size compared to a normal VMU's square display - it's a fair bit shorter vertically, meaning you'll see the bezels through the DC controller window. The same visuals info is still there and in the correct aspect ratio, but it still bugs me.
Also, it lacks the automatic virtual memory card creation and loading based on which game you're playing like the MemCardPro line of cards, meaning you have to manually switch between cards and name them by changing the name of the files on the SD card. This is pretty annoying and made me realize just how much I missed the set-and-forget nature of those cards. But, I suppose it's useful for keeping DLC on the same card as the game that needs it, but I still wish this was an option.
Maybe this could be added in a firmware update, but as of now, a lot of the planned features like PC software for save/device management aren't here yet, and I've already had issues where the device hangs and needed to be force-rebooted, making the software feel half-baked right out of the gate. I'm certainly hoping future updates will bring this device up to par with the MemCardPro in ease of use and stability, but for now, it at least does all the promised basics, which is sufficient for me.