From .009 upwards, these fellas are light, easy to bend, work well with tremolos and sound great on any electric guitar.
For Stratocaster users, they've got the 'quack' sound that is so lusted after.
They're not the cheapest strings around, but they're hardly expensive, and decent (and new) strings do make such a difference to a guitar.
Ernie Ball have been making Slinky 9s since the Pleistocene era (well, for decades) and I wholeheartedly recommend them. And I haven't ever had them go astray in the post.