One thing that surprised me a lot recently, is I started a rewrite of my personal website using Bootstrap as a base, where the old one used jQueryUI... iirc, I included the kitchen sink in the old version.. however, the new one came in a bit heavier on the download/overhead... even with a better min/merge plan.

I can say the new version I am working on looks better, and is actually usable on a phone, just the same, I am not sure I'd like to see the UX on a bandwidth constrained mobile connection.. it's still well under 1MB total, but it seems that we should be working towards being under 100K for an initial load, and given all the targets for different browsers, and work arounds, and libraries, tools etc.. I just don't know where we are going.

We have more target browsers and size constraints than ever, and it's more complicated than ever. I don't miss the V4 browser wars (IE4/NN4) but it seems that targeting a 700px wide or 960px wide site was way easier than the rules today, mobile first or not.