An opinion
Heya ..
Im doing Software Engineering at Usyd, and i did the hardware topic last year and i have to say that if you are planning on doing any sort of electrical engineering degree (telecom, elec, computer, software or ecommerce) that the benefit of learning some basic boolean algebra and binary maths far, far outways the benefits of having the heads up on Object Orientated programming.
One of my subjects is Elec1101 Introduction to digital systems, and the majority of the work is just more advanced and complicated (but fun!!!) methods of designing logic gate circuits. So getting a jump on boolean algebra(again , very very simple) is probably quite beneficial plus as someone posted above things like 2's compliment is kinda difficult the first time you look at it, but its really easy after you get used to it.
On the other hand, if you are just planning on doing straight computer science, well.. its still hard to recommend Evolution(even though i havent done it, but i have looked through it) unless you really have no clue what Object Orientated programming is about. (something about which the basics can be learned in a week). I guess if english is your passion, and you like a topic which you can waffle on about, then Evolution would be for you. If you are more mathamatical by nature.. well then Hardware is definatelty a good choice(im about 50/50 maths to english, got 46/50 for 3u and 94 for 2u and 88,46/50,45/50 for 2,3,4u english respectively).
And.. yeah thats about it, OTOH aparently the question for Hardware last year was a lot harder than the one for evolution, but id imagine they were marked differently ...