Is my reactor any good?

Overusing integrated heat dispensers is bad design (www.talonfiremage.pwp.blueyonder.co.uk/reactorplanner.html?hiw0cj727qyg5f6sc0gwf0h6xwnt05br3u0tet4t9667c75kw). If you are happy with mark II you can try this one from good reactor list:
http://www.talonfiremage.pwp.b…a=1p101010110010101001010 , has higher output (while the cycle is running ;)) and uses less uranium.

You could always go with cheap reactor: http://www.talonfiremage.pwp.b…=1p10101001501521s1r11r10