TeXShop is described as 'TeX/Latex editor and previewer for Mac OS X, written in Cocoa' and is an app in the office & productivity category. There are nine alternatives to TeXShop for Mac, Windows, Linux, Online / Web-based and Haiku. The best alternative is TeXstudio, which is both free and Open Source. Other great apps like TeXShop are Texmaker, Texpad, A.nnotate and TexitEasy.
TeXShop is mainly a LaTeX Editor but alternatives to it may also be Word Processors or IDEs. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of TeXShop.
TeXstudio is an integrated environment for writing LaTeX documents. Our goal is to make writing LaTeX as easy and comfortable as possible. Therefore TeXstudio has numerous features like syntax-highlighting, integrated viewer, reference checking and various assistants.
TeXstudio vs TeXShop opinions
pros, cons and recent comments
Studio has project/session files, saves state of your work. TeX-sync works seamlessly in studio (did not test it for texshop)
Inlage (Intelligent LaTex Generator) is a shareware LaTeX Integrated development environment that allows the user input LaTeX by using Windows 7's Math Input Panel. The shareware version does not allow saving or compiling after 5 minutes of testing.