I have 2 rabbits, a guinea pig (had 2 up until last year), 2 dogs and 2 cats. I'm feeling lazy tonight, so I'll just copy something I posted on another topic a couple of days ago, when we were discussing this very thing!
"As much as I love them, I wouldn't have caged animals again. I used to have a horse and I would almost put them on par with that commitment wise - cleaning out daily, fresh greens every morning, fresh hay and water twice a day, checking them morning and night, cold proofing the hutch in winter, heat proofing it in summer, exercising, nail trimming, grooming etc etc - and it's impossible to get someone to look after them when you go away. Actually, scratch that, I could always get someone on the yard to look after the horse - rabbits are harder! And, as lovely as they are, you just don't get much back from them like you do with dogs or horses. I think a lot of people underestimate the amount of space and care rabbits need, and think they're the ideal pets. When someone asks me for an easy pet, I say get a cat - or a goldfish!"
I definitely think people don't realise the work involved with rabbits and how much space you need. I think people expect them to be easy because they live in a cage, but the opposite is true. All a cat needs is food, water and a litter tray (or a cat flap), other than that they're pretty self sufficient and much easier to look after IMO. Spaying, vaccinations, wormers etc are the same price for rabbits and cats, so cost-wise there wouldn't be much difference. Actually between food, greens, hay, grass, sawdust and willow toys, I probably spend more on the rabbits than on the cats!
I love guinea pigs but just to make you aware, they shed hair just as bad as cats do, and they can't be litter trained (one positive about a rabbit - they can). They'd need to be contained in a large enclosure or cage during the day for their own safety, but you can certainly let them out supervised when you're home.