Hello;
It really depends on both personal preference and what you are reading. 
When I was working I needed to read lots of documents that were primarily 
numbers.  Listening to that gibberish was almost impossible.  An 80 cell 
display was wonderful.  The down side was that all you needed to make the 
thing semi-useless was a bad dot or two.  Buying the the display would be 
difficult.  I wouldn't feel comfortable owning one that was not under some 
sort of maintenance contract.  Bottom line I guess is how many maintenance 
contracts can one pay for?
Now if you are reading text or a novel, speech is faster smaller and 
drastically cheaper.  Variety is what makes the world go round.
Richard