mypressi is a dead/defunct entity...fini.
I had the prior version of the ROK, The Presso from the original mfg, and pulled hundreds upon hundreds of shots while in Land Cruiser mode. Like most espresso gear it has its plusses and minuses: You have to work very, very hard to get "espresso". It can be done but the stars need to be fully aligned

. OTOH its dead simple: No electricity, NO canisters, etc. are needed. Supposedly the ROK iteration is built more solidly to eliminate the handle breakage problem that plagued some of the first gen units (I never experienced a mechanical reliability issue with mine though).
I've owned and used just about every portable espresso machine/maker on the market and all of them stopped short in the real espresso department except the Portaspresso (and the mypressi when it worked...was not reliable...).
Up the ladder in terms of cost and capability would be one of the Portaspresso products: The Rossa HC and PG espresso presses (a couple different variants within each platform). I have the Rossa PG Brass Air Espresso unit (can be used with/without the pressure gauge).
Coupled with my Pharos it is capable of putting out absolutely incredible espresso, whether comparing to any portable or even commercial electrically fed machines,...simply in a league of its own.
Yes its expensive but they are a high precision hand machined product...made in AU not china; you get what you pay for. You do need a way of supplying compressed air...a high pressure bicycle tire pump works great or any other source capable of ~150-200psi.
http://www.portaspresso.com/page010.html
If press style coffee is your thing then maybe the Aeropress or the Espro would be potential candidates (and equally capable at home or in portable mode). Either is relatively inexpensive, mechanically simple, very portable and output super tasty press style coffee. And they are relatively quick and easy to clean. But espresso they're not.
HTHs