iCoolsoft MTS Converter for Mac is a video conversion tool that can be used to convert your AVCHD .MTS files so that you can play them on devices that don't support that format. The .MTS format is widely popular among HD camcorder manufacturers, mainly because it allows for great-looking video and crisp sound. The format is not very compressed, though, so when you convert it to other formats with this application you should notice that the converted file will probably weigh several times less than the original one.
It should be noted that although the MTS/AVCHD format is supported by this application, there aren't any specific features for that format. Thus, the price doesn't seem logical, since other converters by iCoolsoft also support the format and are almost identical to this one.
With that said, the application does work excellently. I tested it with a sample AVCHD file that was extremely big, and with a great resolution. I converted it to H.264, which is one of the most popular formats out there and it works great for HD content. The process was not very slow considering the size of the input file, and the resulting file looked great.
In short, iCoolsoft MTS Converter for Mac is a nice general-purpose video converter that supports the AVCHD format. It wasn't specifically designed for this type of files, so you may want to try other video conversion solutions before purchasing it.