Truth is that you have a simple choice:
1. Whatever is in the 'unstable' repo at the moment, which changes regularly
2. You build it yourself to a specific version
Whether either results in a truly stable build depends to a great extent on what you're using it for... if you never use a function that relies on newer or less-tested code, then you're less likely to have a problem. If you're using CWC, SAT>IP or something more 'unusual' then you're more likely to find an issue (and thus help debug and solve it, of course).
I have a simple multi-tuner, FTA-only, DVB-S-and-T setup, and I find that 3.9.2513~g1d8b541 on 'buntu x86_64 14.04 is rock-solid for me.
I believe the 'beta' repo is 3.5.something, so newer than the 'stable' 3.4.x but still ancient.
Migrating to 3.9.x means a certain degree of reconfiguration because of how the adapter-to-network-to-mux-to-services code has changed. I
believe that your current recording list will survive the upgrade, but TBH it's so long since I did it I really can't remember - plus it's no big deal to me to lose that list, as I can always navigate to the files via a Kodi 'files' source and play them that way.