It's a good thing I use it far less for synchronous vocal communications (read: phone call) than asynchronous information exchange (read: texting and/or data access). The intermittent nature of the service is of far less importance for data than voice. And, for me, it's the data over the voice communication that makes owning a smartphone worthwhile.
Speaking of voice (ha, get it?), I gave Siri a whirl when I first got the 4S a couple of months ago. It was interesting - when their servers weren't overwhelmed, disallowing any information return. Now, it appears Siri has some competition. Evi, created by True Knowledge, a Cambridge, U.K.-based semantic technology startup can answer questions posed by voice (using Nuance software) in a conversational manner or by typing. (Nuance is the current incarnation of Dragon Naturally Speaking voice recognition software. I gave it a whirl back in the late 1990's as an addon tool for my legislative drafting software that I wrote. Unfortunately, it never worked quite as well as I hoped back then.)
Evi is intended for use as a general reference for facts and location-based information (think Yelp or AroundMe). I read that some users have issues with Evi servers being overwhelmed as well. I haven't yet given Evi a try, but being on the west coast of North America, and True Knowledge being in the UK, I anticipate the 8-hour time zone difference alleviating the server load issue for me.
For computational information, I use the WolframAlpha application on my iPad. It's now a mere $9.99 and (for me) exceeds any mathematical needs. I don't know if it matches the overall power and elegance of Mathematica, but for 1/100 the price of the standalone application ten years ago, that's OK.
A favorite query is to input two given names and get a comparative analysis of those two names' use over time. You can do this on the web as well, as they both link to the same servers. I also used it to review my son's homework. He has a graphing calculator, I have Wolfram Alpha.
I think I'll give Evi a go as another handy tool for the computer in my pocket.