Sharp is good. As long as you still have all your fingers and toes, thats the main thing
Re: Machete's, the Ontario ones tend to be heavier than other models, so bear that in mind. I had an 18 inch bladed version that I did not like at all. Unless you are 6 foot four and used to manual labour I would not recommend this one, (I say this having had experience with martial arts sword work as well).
The handles are rivetted on and not very comfortable. The molded handguard versions-a great improvement I read-I dont think you can get in the UK due to the 1988 weapons act.
The Ontario will more than likely chop through branches and similar better than most other machete because it is thicker. Other machetes are not so suited to such work, because they have thin blades, so bear that in mind. You run a higher risk of the blade fracturing.
I've decided to go with the Gerber because I think that it is a design that will work in the UK. Good for clearing brambles, nettles and such like, but also capable of removing branches and similar where needed. Yes, it looks like a billhook, but then the billhook is a time proven design for these parts. Most machete are suited to different vegitation in different climates.