I have used Tobii eye tracker for a project. It is quite accurate and easy to use. They have a number of models so I am not sure which particular model you are looking at. The model I used was T1200 which is a PC based model.
We are just exploring and have not even considered the model.
Our application will be on those with decreases in cognition, but we will not require significant computing. Our priorities are small size of unit and we are concerned about accuracy at larger angles; ie 30-40. The description says "good" but in practice does it remain reasonable accurate at 35 degrees. Again we are at a starting point in understanding the technology plus/minus.
We at orthovision use Visagraph, as is it was our second option Tobii. Have to say that after 5 years we are very happy with the eye tracking results; the test results come in form of graph as well as the detailed analysis of the eye movements. The price difference is very significant as well.