I have not ridden a 450L yet...
With that said, if I were to be spending a KTM amount of money for a dirt bike, it would be a KTM. Sorry Honda, and I ride RED.
As I sit here typing, the 500EXC is the only real competitor to the 450L that I'm aware of. I've been seeing the 500 everywhere, and with good reason. It's a great bike. Tons of power, light weight, electric start (with kicker backup), 6spd, the list goes on. Spending ~$11k for a dirt bike with blinkers is nuts in my book though. A friend of mine has a few year old 500EXC, and I had an opportunity to get a steal on a used one (that I didn't take). With a little help from the aftermarket, they can be everything you want.
In my eyes, the 450L is trying to get a piece of the 500EXC pie. You just have another manufacturer doing the exact same thing as the first one. What Honda should have done is not kill off the XR650R; they should have added electric start and made THAT street legal. the old technology 650R is still pulling big prices in my area. Big power, easy maintenance (key item), aluminum frame even.
I currently ride an '07 XR650L (yep air cooled, steel frame, conventional fork, 340lb, 25yr old technology). It replaced my modded XR400, and have had a list of Honda XR and CR, and even a Kawasaki (KLX650R) in the past. A good riding friend of mine swaps bike frequently so I've had the opportunity to ride an assortment (KXF, KLX, KDX, WR, YZF, DR, DRZ, CRF, the old Husq...) and honestly KTM has done a **** good job of making a "1 bike fits all". I expect the 450L to do the same.
2005 2500 Cummins/48RE/3.73, QCLB, 4wd, BigHorn, Edge Juice w/ CTS + Turbo Timer,Transgo Shift Kit ISSPro Oil and LP pressure gauges, GDP 20/2 filters, Custom Diesel Steering Box Brace
'10 Forest River Shockwave Toy Hauler 21'
Honda EU3000I Genny