Is it feasible to install R14B and stick with it until R15B? Or do i need to be installing the -1 ets as well?
Also, is there no autoupdatable ubuntu package so that I can at least install security patches?
It's not like you sit there typical 'apt-get update' a couple of times a day to see if there's anything new you might want...
On the other hand, people who are new to the language generally like to use the very latest because it contains the most features. E.g. later versions have increasingly good SMP support, which may be important if you're working on something which has to scale across many cores, but it's completely irrelevant to me because our hardware only runs Erlang on one core.
My suggestion for a starting point: if you're just developing, follow the R14 sequence, i.e. every time a new one gets release, download it, compile and install from source. If you're ready to deploy now, use R13B04 and let others find the bugs in R14.
Potential biases: I work at Corelatus. I've worked for Ericsson. I maintain the Erlang FAQ.
There should be backwards compatibility between two major releases, but not more. You could likely go from R14B to R15B, but optimizations and bug fixes usually make it worth it to upgrade in certain circumstances and setups.
I can't help you with Ubuntu, though. That's the responsibility or choice of the person in charge of the packages.