I was undecided between getting the Yamaha P-37D Pianica and the Suzuki M-37C Plus, and after a couple of months I can say I'm more than happy I went for the latter.
The melodica itself is really well made and looks and feels like a quality instrument with the metal corpus. It comes with a pretty handy softshell carry bag and one "goose neck" mouthpiece.
What's most important though is the sound quality, of course. Does it outclass higher end Hammond melodions? Probably not, but it produces clear, consistend tones and certainly sounds like a proper instrument and not a toy. It also arrived in good tune out of the box. I recommend you check out some YouTube videos to hear the direct comparison with the Yamaha - personally I prefer the cleaner, more straightforward tune vs the Yamaha (which reminds me a bit more of a melodeon).
With sound and design being a matter of persoal preference, what makes this one stand out is the goose neck mouthpiece it comes with. Unlike the elastic plastic tubes you get for most melodicas, this one is actually a rigid neckpiece with plastic/metal segments that you can bend in shape. I found this super comfortable and convenient for playing while standing up and holding the instrument in your hands as nothing flaps around. It would have been great if it came with another short mouthpiece, but given that the flexible mouthpiece alone costs around 40 euros, this is really a neat little package.
I would highly recommend this if you want to experiment and have some fun with a melodica that sound and feels like a proper instrument, but don't have the need (or ambition) to shell out the money for a higher end model.