ive never flown a trex XL, but i am under the impression that the x400 is even more stable and beginner friendly than the trex is.

the X400 CCPM version has near ZERO cyclic slop and may even best the trex at that point. the tail on the XL supposedly has less slop than the x400's trex v2 design. i also have the XL t/r pitch slider system on my x400 and didnt notice any difference.

id say for the price, the x400 makes a good competitor. it lacks the popularity and parts distribution.