Am I missing out by not rooting my phone?

Which phone do you have? I have rooted every phone and tablet I have ever owned.

I highly recommend it, but that's just me

It took me a while to get started rooting and flashing roms. My first brush with Android was the Sony Xperia x10i with eclair which was upgraded ota to froyo. Then I got my SGS as soon as it came out. I rooted it but no custom roms, it was for the apps, titanium back up etc. But now with my SGNote, It was rooted after a few weeks of using it and I bricked it flashing a leaked ICS ROM (I could not wait for Samsung). BUT Samsung fixed it (with no charge and their tech installed the abyss kernel for me) and I've learned a lot since then.

In fact my tablets (TF Prime and Kindle Fire), phones (SGNote and SGS) are all rooted and running custom roms with performance tweaks. Tablets are overclocked for gaming and video performance. Phones are underclocked and undervolted for battery life. I guess once you get started, there's no looking back.

Just be careful, read and re read the instructions and look at the discussion threads for potential issues and to see where others went wrong. I was just lucky Sammy PH played nice with me and honored my warranty despite the obvious flash counter increase and an ICS Kernel and ROM residing in my wrecked phone. Otherwise it would have been USD 300 for a motherboard.