I have owned (3) recent KTM's (500 XCF-W, 450 SXF, 350 XCF-W) and (5) WR450F's.
Here is my evaluation of the difference:
KTM's (all): feels light, is light, very small cockpit, very steep head angle, very soft power delivery (very) and merely adequate suspension even AFTER reworking. 2013 and later are very reliable.
These bikes require more rider input and concentration when going fast than any other bike I have ridden. The require LESS rider input when going slow. Much less, but only when crawling.
The strong feeling of 'yogurt-soft power and suspension' really hampers these bikes for agressive riders. (Dirt Bike magazine quote...)
WR's (pre-2012): feels heavy, is a little heavy, but not a deal breaker. Once uncorked, GREAT power quality, with tons more available, GREAT neutral handling at all speeds. Stock forks need work.
Fun fun fun, describes the WR handling. Rider input is not hyper critical like the KTM's when at speed. Very relaxing to ride fast or slow. Heavier feel on really tight vertical stuff.
Stone cold reliable. Probably the most reliable dirt bike every made.
WR's (2012+) : very similar to previous WR's, but slightly smaller cockpit (especially peg height from ground), MUCH BETTER EVERYTHING especially suspension.
Best suspension all around (but too soft stock)
Stock needs GYTR kit, period. Can't ignore this. Still very neutral handling at all speeds
Still the most reliable.
If weight, and the appearance of being adorned with high end parts is extremely important to you, (more important than robust power or neutral handling) then the KTM is the bike for you.
If you want to play MX, spin the rear wheel on command, steer endlessly with the front or rear wheel, actually ride FAST in rough terrain, then the WR is for you.
Edited by Kah Ran Nee, February 28, 2015 - 07:20 AM.