Dude this is awesome. I use LyX all the time even though I'm perfectly fluent and capable with LaTeX. The immediate feedback you get from it means I can spend less time worrying about syntax and more time thinking about mathematics. I often don't even write on the board or on paper, I just go straight to LyX; I'm fast enough typing in it that it's the same.. plus my notes are instantly typeset beautifully. Also not having to do a makefile to handle the massively convoluted commands to compile LaTeX that uses lots of necessary packages (e.g. BiBTeX) is a huge productivity boost.
LyX does have some failings though. I learned with my thesis that it's not yet ready for a serious long-term multi-document project. Some of the LaTeX details are insufficiently exposed, and so when tweaking is necessary it's difficult to get under the hood and make something happen that needs to happen (like once I couldn't get linebreaks in figure captions.. Simple in LaTeX, but in LyX...) Sometimes when it IS possible to do LaTeX tweaking it won't behave nicely with LyX because LyX isn't technically a LaTeX frontend, it uses its own typesetting language and converts at compile if you want e.g. a pdf in the style of pdflatex. One example of this is putting in \noindent to remove spurious indenting after figures,equations. Put it next to text in LyX and it won't compile even though it's in its own LaTeX environment.
For small projects those things aren't really a big deal, you get by with a workaround.. but on a huge project like my thesis you have put in so much work and already have a huge base of work that the little things just need to work, because you can't just say "oh well just won't do that thing." Also the errors you get at compile are all LaTeX errors, which even if you're editing a LaTeX document aren't terribly informative, but editing LyX it can be next to impossible to tell where that error is coming from without exporting to LaTeX and looking, which costs time.
Still.. Fix these things, and LyX has the potential to be a massive productivity tool. Many of the proofs in my thesis I directly began in LyX without working out on paper beforehand, and then edited it for prettiness later. It's the perfect balance between proper typesetting and what mathematics gets presented to the user. WYSIWYM as the LyX folks say, but still usable as a notebook for on-the-fly work.
Some features I'd love to see is a solid symbolic math interface. It has one currently but it's limited. Scientific Workplace has an *excellent* symbolic interface, and when I used that (which I don't anymore because it's not portable across multiple OS) I had a huge productivity gain. Imagine typing in a frustratingly complicated integral that you need in a proof, and just highlighting it and typing "Ctrl+e" and it spits out the typeset solution before your eyes IN YOUR DOCUMENT. Sure you'll have to edit it down because likely it will exceed margins, or isn't exactly in the form that is most appropriate for the context.. but that's editing work that you'll have to do anywhere anyways. I'd also like to see a better supported nomenclature package, which is currently a tad buggy in LyX (random deleting of nomenclature entries, no way to browse nomenclature entries throughout document without resorting to ctrl+f, etc).