I have not used them as much since finding other alternatives, but the one I have used was ReMask.
It comes in handy when trying to mask out really fine things such as hair or tree limbs and branches, but there are many other things it can be useful for to reduce post time.
I like using the tried and true methods, but in a pinch if I am on a time crunch, I will resort to using a plug-in to help speed things along, but only if the results are decent. otherwise it is just wasting time.
Re-mask is okay, seems a little simplistic in the interface, but when you zoom into photos extensively, it renders pretty good results. In a sense, all it is doing is a streamlined process of re-define mask in PS.
I don’t use Topaz. Most of my photos only get a couple of minutes of raw conversion and editing so I don’t think plug-ins would improve my work flow. Masking tools in PS CS5 and CS6 are pretty good and complex masks can be created quite quickly. When necessary, I use the noise reduction in ACR, which has been adequate.
I’ve got them all but rarely use anything other than remask, which seems great at really hard jobs and then seems to struggle with things that you’d think were easy. Topaz BW effects can do some nice things but I find the BW in Topaz Detail is good as well, though both need time to load up. If you REALLY know PS I doubt it would speed up your PP.
I also find that, since I’ve downloaded the trials, ReMask is the only one that holds any value for me, and that value is even marginal. Most of my PP is just as CameraClicker wrote “a couple of minutes of raw conversion and editing so I don’t think plug-ins would improve my work flow.”
LR5 brings so much to the table there is very little need for “something more.” I rarely need to wander from that program. I guess those programs are for a segment of the community who have not taken the time to explore all the lightroom