I don't see how anyone who likes old school heavy metal wouldn't like Manilla Road, especially if they also like old thrash and power metal. Mark Shelton is an excellent and really versatile vocalist, although his singing on many songs isn't as immediately accessible as someone like Bruce Dickinson. As far as instrumentalists go, they also outpace most other bands and they have songs covering a lot of different territory.
I haven't heard any of the newer albums, but the songs that I heard from them were all excellent.