This is, as the name suggests, a special edition of the OG MPC X, not a major upgrade. The SE features a vintage colorway, 4 GB of RAM (instead of 2), 48 GB internal storage (instead of 16), and comes loaded with almost all Akai plugins and some of the expansion packs. Ironically, despite the vintage styling, Akai was too cheap to include their vintage-ifier plugin Air Flavor Pro, nor the Mini D or the new Delay Pro plugin. I'm not 100% sure exactly which expansion packs came with it, as I already owned quite a few, but there were definitely some that I didn't own previously.
So, should you buy it? Well, as always, it depends. If you already own the OG MPC X, it's not worth shelling out $$$ for a few plugins, expansions, and a slight upgrade in storage and performance (or the vintage look). If you're upgrading from the One (like I did) or the Live II, it might be worth it if you have the money, but consider that a used OG MPC X will cost you less than half of the SE.
Pros:
The 4x4 Q-Link panel (OG and SE) is a game changer. I had thought that it would merely replace the need to push the Q-Link switch button on the One to switch the screen controls, but the Q-Link panel on the X (OG and SE) is also activated when using, for example, the channel mixer (to directly control the levels or the panning of each channel from the Q-Links), or the main screen (to tweak various sequence and track parameters). If you are using a CV program, the Q-Link panel allows you to control the voltage of the CV outs (and thus your modular synth) from the bottom two rows of Q-Link knobs - that's significant for me as a Eurorack user. There are probably more uses that I haven't discovered yet.
The 10" screen is a godsend for my ageing eyes.
The pads are bigger (OG and SE) - I'm not the world's greatest finger drummer but I like it.
Plugins load noticeably faster on the SE. On the One, it would sometimes take up to 7-10 seconds for a Fabric XL preset to change/load; now, this takes 2 seconds max. This isn't a very scientific way to assess it, but it's noteworthy nonetheless.
Cons:
It's quite large. I was aware of the dimensions when I ordered it but was still surprised by how big it is IRL. It's not very portable at all. That being said, it looks gorgeous.
Akai's customer support is absolutely useless, but this isn't specific to the SE.