Hearing good things about PR agencies is one thing, how it turns out for you is something else entirely.
These 'good things' - oh it all sounds great etc, but viewing the press page/results for one company cannot give any indication of how a campaign will turn out for you.
This will cost you hundreds and hundreds to do a first press thing, personally, if you're idea isn't brilliant, unique, I'd forget the media entirely, bcos the return won't be there, infact the media won't touch it - see they like uniqueness and they have the power, not you.
It takes too long to achieve results and if you think it's like coming out of the BB house, then your in for the shock of your lives. If you don't believe me, then fine, but I've done this and you'll be sitting there and waiting for over 12 months easily, while the agency will use your cash up, keeping you hooked, then without warning, you'll hear nothing from them, which signals the end of your contract hehe.
BTW, the agency we used was a top london international agency, which appeared to have a solid track record, but you won't know until you hire an agency and they start working for you. Too easy to get it wrong, so easy to make a mistake and:
- either pay too much
- hire the wrong people.
Just be careful who you hire..... and never, ever hire based on what results they got for another company. You don't know how much the other company paid them for those results/time. I'm not saying we got ripped off, just that we didn't get good value for money.
PR agencies will typically ask for money upfront eg: 3 months worth, this ain't cheap folks

, and you got to keep on top of these guys, don't just trust them or leave them to it, keep checking on them. Trouble is, once you paid, you paid and you've done your cash, so you are really in the lap of the gods where the press is concerned.
This is NOT an instant results kind of thing!!