The stable tree does matter a lot! In fact I love the stable tree and the fact that Debian doesn't have a release every 12 months. We all have more important things to do than perform OS upgrades.
If you ask me, an OS upgrade that is more frequent than 24 months is unproductive. I simply don't have time for that crap. So, I honestly do love Debian's slow releases.
(Plus, one has to ask oneself - how do the other more "frequent" distributions manage to fix all bugs so much faster than Debian in order to release? The obvious answer, which I have alas suffered through, is they can't and they ship with more bugs)
BTW, we manufacture appliances which run Debian (with some non important customizations). We always stick to stable, so we have it on our development machines and on our target hardware. It would really suck if we had to change everything every 6 or even 12 months. As it is, we have an OS that matches our business model perfectly. We could be in the minority though...
(We have considered Ubuntu LTS and it would probably work for us, if Debian disappeared, or, God forbid, started making more frequent releases)