what are your opinions ?

The new four stroke quads are fast and have nice suspension set ups but I just love the two stroke zip.  You just don't get that with a four stroke.

you can buy a used zilla, fix it up, and it still be cheaper than buying a brand new 450.  Much faster too.  And they turn a lot of heads.

Both have Pros and Cons, Cost wise maintenance wise the 2 stroke is easier in my opinion, The cost to Hot Rod a 4 stroke is how much money you got is how fast you can go, pipes $500, Pistons $250-$400 Larger Valves 55 to 65 Ea Porting the head $350-$1500, Carbs $250-$500 EFI Programable Controllers $250- $500 CDI Box $250 -$500 Cams $265- $400 H/D Valve Springs $125- 250 it all adds up, not counting Big Bore Kits , Stroker Kits, easy to spend $3000-$5000 for 60-65HP 

Where a LT500 for around $3000 for complete rebuild Bottom End Top End - Porting - pipe - carb 65 to 75 HP 

But hey, I love my DS730..electric start ya know.................

I love my 450. Easy to start, handles good, and it fast but.........the 500 is really fun to ride. The 2 stroke snap zip whatever is intoxicating. The sound, the power, the smell!

I love my LTR, seems like the torque is a lot better than the LT's but the top end just doesn't wring out quite as well.
My 250 had a good 20mph more top end than my LTR.
However, the LTR handles considerably better than any of the LT's and in endurance or all day riding, at the end of the day it means you're faster.

I love the power hit, pull, revs, and sound of a two stroke.  Two stroke are simple and cheaper to maintain than a 4 stroke, but 4 strokes dont need to have the top end rebuilt as often. 4 strokes are cleaner.   My perfect quad would be a lt500 motor in a well suspended modern day quad with dare I say..electric start and reverse.....  my zilla is easy to start but I must say it is enjoyable to hit the electric start button on the raptor.   I still prefer a a big two stroke.