You can also download PDF of a handy reference chart from the article called "The level Measurement Continuum" which allows you to see visually what kinds of devices work well in what sorts of applications.
If you want to go deeper into the subject, David Spitzer and I have written several books in our "Consumer Guide to..." series about level measurement instrumentation, including comparison charts that allow you to compare the
specifications of most manufacturers' products, as well as see who private labels for whom.
This search on http://www.controlglobal.com pulls up several excellent white papers as well as more articles on level measurement: (mind the line-wrap...) http://www.controlglobal.com/search.html?sp-q=level measurement&sp-p=all&s
p-x-1=section&sp-q-1=&sp-x-2=spk&sp-q-2=spkcontrolglobal&sp-i-2=-1&sp-x-3=ve
ndor&sp-q-3=&sp-p-3=phrase&sp-x-4=&sp-q-4=&sp-x-10=url&sp-q-10=&sp-q-require
d-10=-1&sp-t=cp&sp-a=sp10033b41&sp-k=&sp-sfvl-field=section&sp-c=25
And if you have specific questions, we are all ready to help.