It is fast, but it does take quite a good amount of skill and experience to be effective with it, and it isn't just Raiders and Assaults that can take a Scout out. I took on Scouts in an Infil and did alright in the recent tourney (though admittedly I've got quite a lot of experience with the game and the Infil), and it's also possible to take 'em out with heavier mechs, or mechs with a good amount of splash damage weapons.
The main problem players probably face is that when they're up close, their speed makes it difficult to keep aim on them, and panicked pilots will probably hit the turn rate cap even more during this time. Pair that with the ridiculous amount of close-up power potential with no repercussions when the Flak or Mini Flak are used and it makes for a particularly deadly adversary.
Perhaps a big reason they seem so dangerous is because many of the higher-skill pilots use them effectively, and lower-skill pilots haven't yet developed the muscle memory or strategies to counter them.
Edited by -Tj-, 31 March 2016 - 09:01 PM.