ionGrid is in the process of trying to onboard some new Mobile Engineers. I had never heard of ionGrid until my pushy headhunter pushed me their direction, and the reason I've never heard of them is that they operate in the low-key, enterprise (or, in layman's terms, business) oriented world of collaborative cloud computing. Their main competitors are Good and MobileIron, both of which are likely to be bigger and better established (Good Technology has been particularly active on LinkedIn and the job boards, trying to go after mobile engineers).
A typical interview series with ionGrid starts with a telephone screen and I jumped through the few technical questions without too much trouble (I can't find my notes on the questions that were asked on the phone so I'm guessing they weren't too big or horrible).
Step # 2 is an interview day, where they prefer the candidate to be in the office for at least four hours in the afternoon.
ionGrid's office is in an unassuming, unadorned (no signage aside from the address) former storefront on El Camino, strategically positioned physically between the Mobile Computing powerhouses of Google and Apple. Street parking can be found in front but there's a big and free parking lot behind the building and they're a 10 - 15 minute walk (or 5 - 6 minute bike ride) from the Mountain View train station. There can be anywhere from between 7 - 10 people in the office on the day of your interview. Everyone appears to have a nicely sized cube-let (half height walls, giving an illusion of a bit of personal space, but everyone is visible from everywhere else in the room). The back of the building is a combination kitchen and meeting area with a bathroom off to the side and the interview-standard white board on the wall. That's where the interview happens.
Most of the technical interviews I was asked had very little to do with the actual job or the role, but instead seemed to be focused on seeing if the candidate is simply smart enough to pass a graduate level algorithm's course exam. The one and only dedicated to iOS guy brought a notebook with questions which were Objective C and iOS coding based.
Another one of the engineers, a math graduate, turned out be super condescending: "you haven't seen this [calculus] stuff since high school so it's understandable you may have forgotten it". That snub, combined with my brain-freeze (or panic) inspired frustration & humiliation, angered me intensely and I was seriously considering walking out of the interview at that point. I calmed myself down and decided to stick around for the following interviews, to see what the other potential co-workers would be like.
The most affable person out of the whole collection of people I spoke with was the CEO, who is definitely the big picture guy of the group, and I liked talking with him about the viability of iOS & Apple (where the CEO used to work) versus the intense competition from Android (which is the more popular - and utilized - platform outside of the U.S.).
This is a private company (which is apparently just about to cross the boundary into being cash flow positive). The big (or only) benefits for a developer to work here appears to be predictable hours and what is likely to be a non-high-stress work environment (aside from the technical interview bits), while still appealing to those who like to hack and push the limits of what Apple and the other OS manufacturers might allow into their app stores (which a couple of the engineers bragged about). If you have a specialty such as iOS or Android or anything, this might not be something they'll encourage going forward, as at least a couple guys talked about using PhoneGap or other architecture-independent solutions that alleviate need to be specialized on any particular mobile platform.
For me personally, after getting demolished by the Math guy, I realized they're looking for academic smarts and not necessarily practical smarts or experience, and that ionGrid wouldn't be a place where most engineers could easily integrate well into their somewhat close-knit family of snooty nerds.
But hopefully documenting my experience at flunking this IonGrid interview will help you to be a better candidate. Good luck to you here!