ive got an halo too bought new for £58 about 18 months ago, at the time rotors were twice the price, all halo's are solid loaders never had any problems and upgraded to a prophecy i was that impressed with the halo too, but unless you can pick up a cheap halo its worth spending a little more for a rotor as 2 or 3 are used by team-mates and rotors seem to perform really well, and so efficient on batteries and they hold their price on the second hand market
if you can afford a rotor they are better than a halo too but if you see a 2nd hand halo too for £25 ish delivered you can't go wrong for the money!