If have come to greatly appreciate Lyx' [1] WYSIWYMean approach. When you are mostly writing code or plaintext markdown is great, but if you have to typeset and edit a lot of formulas using Tex quickly becomes a pain. Lyx allows you to edit them graphically with the standard Tex syntax and displays them while you type which is a huge improvement to just rendering them after you have finished it. Unfortunately the videos I've found online all heavily use the mouse interface to choose subscript, special characters etc. which doesn't do Lyx' real efficiency via keyboard shortcuts justice.
If you want to try it yourself: The most important commands are [ctrl]+[m] to enter math mode (or [ctrl]+[shift]+[m] for display formulas) and [alt]+[m] for a lot of math shortcuts, specifically [alt]+[m] and then any bracket to open matching size adapting brackets of this type. To enter a sum for example press "[ctr]+[shift]+[m]\sum[space]_k=1[space]^\infty[space][space]\frac[space]1[down arrow]k^2[space][space][space]". The shortcut [alt]+[p] and then [space] to choose the paragraphs meaning (section, itemize, standard, …) is also a huge productivity boost.
If you want to try it yourself: The most important commands are [ctrl]+[m] to enter math mode (or [ctrl]+[shift]+[m] for display formulas) and [alt]+[m] for a lot of math shortcuts, specifically [alt]+[m] and then any bracket to open matching size adapting brackets of this type. To enter a sum for example press "[ctr]+[shift]+[m]\sum[space]_k=1[space]^\infty[space][space]\frac[space]1[down arrow]k^2[space][space][space]". The shortcut [alt]+[p] and then [space] to choose the paragraphs meaning (section, itemize, standard, …) is also a huge productivity boost.
[1] http://www.lyx.org/WhatIsLyX