I have used both Poorboys Trim Restorer and Black Wow and they both have great features. Some people dont have good luck with BW because the trim has to be thououghly cleaned with 50/50 alcohol and water before application. Depending on how bad the plastic is, it also may take 2 coats of BW. I got about 4 months out of BW before reapplication. Also, very little BW is needed to do the trim.
I just recently used PB's Trim Restorer and also liked it. The trim restorer is very easy to use. Just apply it to the plastic, let it soak in for a few minutes and wipe off - a second coat was not needed. Afterwards, I applied a coat of 303 Aerospace Protectant for UV protection. So far I have only had the PB trim restorer on for a month so I cant comment on the durability.
Both products are great, but I think the best all around product would be PB's trim restorer for price and ease of use.