In my experience (DS is 5 months)
Pros
Less faff than making bottles.
It's free (although some of the equipment required is expensive: breast pumps if you're expressing, nipple cream, nursing tops... But it's cheaper than formula still, I'm sure).
It's nice to be able to comfort them by feeding. I don't think, if I was FF, I'd be able to feed them as often as baby would be massive! So I'd be a bit stuck when he was upset if he'd just had a bottle.
Nappies are much less unpleasant.
Apparently they are less colicky if breastfed.
Your stomach deflates a lot quicker because breastfeeding pulls the muscle back into place.
Cons
Painful for the first month or so. The shredded nipples are agony at first.
If you're not an "ostentatious breastfeeder"
it can be stressful trying to time feedings so that the baby isn't hungry when friends/family/health visitor are round or you're out in public. Or, you time it perfectly, and then some fucker that said they'd be there at 11 doesn't turn up until 1145, and then it all goes to shit. 
It feels like they are feeding constantly at first. Which makes point one and two above worse.
BF babies are usually slower to put on weight. Which is stressful, as health visitors who are a bit shit mine make you feel like it's your fault.
You're more sensitive to comments that people make like "Oh that sounds like a hungry cry", "are you hungry", "when was he last fed", etc. Then see point two; if you're out and they're hungry it's harder to find a place to feed privately, whereas you could bottle-feed anywhere.
Typically, breastfed babies wake more during the night.
It's quite hard work on your body; I've struggled to maintain my weight and I assume that's because I'm feeding. But on the flip side, if you want to lose weight, it helps.
You can't really leave the baby with anyone else and get a break.
Leaking milk during the night at the beginning is really unpleasant.
I'd say it is worth it though, and it all gets easier the longer you do it.