There are similar things but nothing is really like ACID.
I tried them all. The closest candidate is Ableton.
The stretch alogorithms are not in the same league as ACID.
There are more parameters in Ableton for it but whatever you do it never sound as good as ACID.
With drum loops you won't notice but try a bass or acoustic guitar.
Very smooth in ACID. No artifacts and best of all it plays right out of the box, no tweaking.
Since ACID is now rewire-slave I can run it with Nuendo/Cubase and were able to drop Ableton.
Ableton has nice FX's though.
ACID was the reason I bought my first PC.
And now I don't have a Mac anymore.