I rooted my A100 a few weeks ago and am very happy I did so - and I'm, sure you are already aware of the usual heads-ups that you'll void your warranty, that you may brick it if you F up and that no one but you can decide if it's wort it to you
When I rooted I followed these instructions and it tool about 5 mins in total: http://forum.xda-developers.com/show....php?t=1531646
Note that I did it on an A100 but according to the instructions they are for both A100 and A5xx.
The most common miss people apparently make is not to follow the instructions and download the latest drivers so make sure to do that IF you try this, or any other method requiring it.
I did a short write-up here about what I ended up using my newly found root-power: Finally rooted :)
I've added some apps since then and may update the post with those findings as well (such as boosting speaker/headset volume, etc).