Step 1
First, divide the chars in groups of three, like this:
XXR KUX IQX XXX LLR YIX RVY XII XPV ZXA QKY IXH PSC ZWE IJF XGY IXH CHS HGI XXM XIE URI RUE BHI XIX REO XCN LTT TXI
Then, count the axial symmetries on every char and transform the chars to numbers:
220 112 202 222 000 122 011 222 201 021 011 222 001 011 200 201 222 120 202 221 221 102 011 122 222 012 210 011 122
Now, try to see the numbers ternal, with number base 3:
24 14 20 26 0 17 4 26 19 7 4 26 1 4 18 19 26 15 20 25 25 11 4 17 26 5 21 4 17
Now this represents the alphabet, 0-indized, and 26 is space key:
YOU ARE THE BEST PUZZLER EVER
and I made a mistake I didn't notice myself: It resulted in the code for
YOU ARE THE BEST PUZZLER FVER
Sorry. And I am not :)