The benefits for me is that I already had the persona as a contraceptive, so I just carried on using it when I wanted to get pregnant. Think it's about £10 for 6 sticks, but of course, the initial outlay is quite a lot (I forget how much now) and you have to use double the amount of sticks the first month.
I think if you already have a persona for contraception use, then you might as well carry on using it. Otherwise I wouldn't bother and would take a closer look at clearblue.