I have the older model monochrome twinscope. The color version is an easier to read, better unit. It is not a true sidescan like the Hummingbird. You have to read and understand the manual for the twinscope to be able to use it most effectively: The information on the screen is not intuitive, and slightly more difficult to understand than a radar screen.
It is good for reading the bottom and what is ahead of the boat in the profile view. The horizontal view is intended to spot bait balls to either side of the boat or the outline of a submerged wall or something (it is great for identifying a channel). It does not have the resolution to identify anything but large features.
Do I like mine? On the whole yes, it povides more information than a standard depth sounder. If I were buying one today I would probably get the Hummingbird though. I am a diver and seeing detail on the bottom is more interesting to me. If you are just interested in what to avoid with the boat or where the fish are out in front of you, the twinscope would work.
Have boat, will travel.