Will I notice the benefits of changing wheels? I've got a 2010 Specialized Tarmac Comp. The wheels are Mavic Aksiums and are pretty well known to be dam heavy (but sturdy)

I'm seriously considering swapping them for something like Fulcrum Racing 3's, that alone should save around 500g

I've never ridden another bike and never changed wheels before so will I notice a reasonable difference and do you think its worth swapping them for something like the Fulcrums?

Interested in peoples opinions pros/cons.

I weigh 80kgs ride a mixture of flat to very hilly terrain and approximately 80-100 miles / week
I think probably swapping your wheels out is just about the single biggest improvement you can make to a bike in terms of performance.

I did this last year and love the new wheels. I too was riding Aksiums (I think) and bought some Fast Forwards. Qualitatively I am very impressed (but then I should be, if you boil everything down to money the FFwds cost 5x a set of Aksiums). Quantitatively, its difficult to say how noticeable the change is. I didn't see my average speeds jump or anything, at least not enough to notice. (I certainly notice being blown across the road sometimes (6cm rims), but that I'm not sure that counts!)

But now the caveat.....it all depends what you swap them for. I have no experience of Fulcrums so can't say how good that particular swap would be. Possibly someone else could help there. All I would note is that they're still toward the lower end of the price range (when you think you could spent thousands on wheels), so possibly they might not make as much difference as you'd hope. But as I say that's based on a hunch rather than direct knowledge.

One other point: not so long ago I had a spoke go on the Ffwds. Was a real pain in the ass to get a replacement (they were fancy bladed DT Swiss spokes and you're always recommended to change like for like). Nobody in the UK could sell me just a handful of spokes, only a box of them at about £100. In the end I found a place in the US who would sell them singly, just for a dollar or two, but it cost in terms of delivery and duty. I'm just saying, whatever wheelset you get it might be worth making sure you can source spares for it easily.