Are there any alternatives?

Yes, but they’re few and far between:

　　Keychon K3: It’s much cheaper than the MX Mechanical and still comes with low-profile mechanical switches. It doesn’t support Logitech Flow, however, and it uses strictly Bluetooth for the wireless connection.Logitech G915 TKL: A gaming take on the MX Mechanical for a much higher price, the G915 offers a similar build and typing experience. It’s much more focused on gaming, with dedicated meta buttons, a volume wheel, and per-key RGB lighting.

How long will it last?

Low-profile mechanical switches have a life span of 50 million keystrokes, so you can get several years out of the MX Mechanical before you need to replace it. Unfortunately, it doesn’t have hot-swappable switches like the Keychron K7 or K3, so you can’t extend the life with a switch swap down the line.

　　

Should you buy it?

Yes, especially if you have a mouse that supports Logitech Flow or toggle between devices often. You can get a similar typing experience for less with something like the Keychron K3, but no other peripheral maker has the same combination of features that Logitech is offering with the MX Mechanical.