Hi @ironmathyu5 and thanks for your query. If you could kindly let us know in further details what your intentions are for the eye-tracking hardware we would be better placed to deal with your question.
However, broadly speaking there should be little difference in spatial accuracy of eye tracking between the 4C and PCEye. If your intention is to use the products for a complete windows interaction solution then the PCEye is more catered toward this need by including support for various features such a speech recognition, switches, etc.
The 4C however is primarily catered toward gaming and windows interaction in conjunction with a classical mouse and keyboard setup.
Be aware however that regardless of which eye tracker you purchase, ‘mouse emulation’ using an eye tracker will never provide precision accuracy due to the inherent movement in the human eye even when focusing on a stationary point, so please consider that.
That being said, software solutions are available to work around this problem by providing ‘zooming’ options during mouse tracking such as the Tobii Gaze Interaction Software designed for Tobii Dynavox Trackers (such as the PCEye).