I am running texmakerX because it was recommended in tug.org as part or the protex package they do for windows. Under ubuntu and trisquel (linux distros) I use texmaker (the original) since it was the fist i found in the software centre. I am low level user and find little difference.
TexmakerX does the job incerdibly well (thanks developers!) for me right now but if i wanted to upgrade to texstudio would I just need to install texstudio on top or would i be better off uninstalling texmakerX.

One thing i noted that texmakerX makes reference to the spelling dictionaries to an out of date diccionary repository for openoffice.