Welcome to the forum!
I'm new to this so have limited experience with other lenses but can say for around the $150 mark this lens does what it is designed to do,and with all the feel of yesteryear!
it is long when extended
it is noisy focusing (video sound recording wise)
it has a quite audible "IS" whir sound (video sound recording wise)
and can sound a bit clunky when tracking a moving target (video sound recording wise)
it is fairly heavy also
It suffers at the ends and is best between 120--250mm in my opinion.
In great light it works like clockwork and is fast and precise focusing but on a dull overcast day gets a bit lost in auto focus hunting.
on the other hand
it does not rotate the front/filter when zooming but it does when focusing!
it has fair optics for the dollar and for a buy/try could be sold easily after some use if it is not what you want.
The "IS" works fine but you get some correction twitch occasionally as the "IS" over corrects itself (especially in poor light).
It might pay to borrow one or go to a camera shop and use one for a few mins with the video side of things.
For me it was a no-brainer at that price point and will have to keep me happy for another year or so.
when I go full frame it will be the 24-105L with the 100-400 L IS USM
the sweet spot for the 100-400 is around the 320 mark from some of the old reviews I have been reading and may be worth considering also.
as I said "my experience is limited " so Doug and others will have a better knowledge of the more technical stuff.
I want to stand as close to the edge as I can without going over. Out on the edge you see all the kinds of things you can't see from the center.