both are reputable (and technically on a high standard) VACATION (Charter) airlines.
Condor is a 100% LH airline (and you can get some minimal LH-miles&more miles if you book with them).
LTU has been bought about two months ago by SWISSAIR - but so far no inclusion into their (Qualiflyer) ff-program. Swissair became trough this acquisiton one of the three major charter players in Germany (the others are Condor and Hapag-LLoyd).
Make your choice looking on the specific package value they offer - and forget about any ff-program!
[This message has been edited by Rudi (edited 03-09-99).]