-- Revised 12/10/2016 --
Among my "IoT computers" or "smart controllers"* (needs a better name) aI have 7 processors from Particle: 1 Core (now superseded by Photons), 5 Photons and 1 Electron. Particle Photons are rather like souped-up Arduinos with built-in WIFI and cloud services. This cloud provides not only the expected variable/function and publish/subscribe services but other handy UNIX-like functions like date/time. Since the summer of 2015, I have had 2 Photons operating in the real-world in my farmer granddaughter's semi-automated hoop house. I had planned to use Raspberry Pi's for this but the Photon/cloud was just too handy. However, an RPi keeps track of things from 100 miles distance.
Anyway, back in August, I emailed Particle.io support that they should provide their cloud interface for the Raspberry Pi. I was probably not alone in this. And now, I just signed up for their beta-test RPi cloud interface. It should be very convenient for me and even if 1% of the 10M RPi's sign on, it should be a good deal for Particle.
REVISION: Well, it's been a month+. Particle has yet to provide the obvious (to me) cloud interfaces for the RPi that match what I can do with a Particle Photon. Like, how to publish to the cloud, subscribe to the cloud, call a cloud function, read a cloud variable? Disappointing! But see post 109.
* I also have 4 Raspberry Pi model B (from earlyish to most recent) and 4 Arduino Nanos. To those not in-the-know, an RPi B is $35 (well, $50 with flash card, etc.); my Nanos cost $7 and Photons are $19. My Particle Electron (Photon with built-in cell modem) was time and $ wasted, for me.