I had never owned Guinea pigs before I got my boys. I rescued a pair of boars back in January this year it was the best thing I ever did. I'll try to summarise the pros and cons for you.
Let's start with the the cons as I like to end on a positives:
1 - Boars occasionally scent mark around their territory and occasionally on you and it smells nasty (fishy to be precise) but this is nothing that can't be resolved by washing your clothes / changing the bedding.
2 - Boars can scrap and fight with each other after you clean out the cage or bathe them etc because you've removed their scent, so they have to establish who's boss again. But a well bonded pair of boars can get along just fine with minimal fallouts if you set the cage up right and have at least 2 of everything.
3 - Boars need their private parts and anal sacks cleaning every so often as they rub their bottoms along the floor when scent marking and this means that they collect bits like hair, hay and poo chunks inside their bums. They can also suffer from impaction when they get older if they aren't cleaned regularly. It's not a pleasant job, but if it becomes a regular part of your grooming routine then they and you will soon get used to it.
4 - Boars grease glands can sometimes be very active and require regular cleaning.
The pros:
1 - Boars have individual personalities just like sows which you'll grow to love!
2 - They can be just as cuddly and loveable as sows
3 - They are gorgeous
4 - They are inquisitive and will wheek for food when the fridge opens
5 - They are every bit as wonderful as sows and shouldn't be over looked!