I don’t find my boys fight a lot, nor do they smell too bad if the cage liner is kept clean and changed regularly. Whether guinea pigs fight is dependent on how well bonded they are.
I didn’t find the teenage stage too bad, at that time the two boys I had were Little and Honey, and honestly their bond could have been better. I got lucky in the sense that they did at least get on as I didn’t know what I was doing and just threw them both together not knowing the potential consequences of that. But, I didn’t find the teenage stage to be worse than any other time, as they got older - around 4/5, they definitely mellowed out a little and the dominant pig felt quite settled in his role so there was little need to show dominance unlike when they were younger i suppose. As I said, I don’t remember it being bad at all, and if it was it only lasts for a short period of time and it isn’t enough to deter me from getting boys again.
Now, the boys I have are Little and Peanut, and their bond is really good. They were bonded by one of the recommended rescues on here. They do still fight at times, it is usually in accordance with illness though. For example, the dominant pig went blind in one eye and so became more dominant as things were a bit more unfamiliar to him. Then the same pig also recently became quite ill/stopped eating etc and you could see there was a shift in hierarchy as the submissive pig began taking charge and instigating fights, once the dominant pig began to feel better there were then fights which he would instigate in order to reinstate his position as top pig. Nothing has ever been too bad though, just some telling off, a bit of chasing and nothing more.
Like I’ve said too, it is all bond dependent but you can expect guinea pigs to be dominant when their leadership is being threatened which can be when illness strikes or when there is a change in environment too.
I don’t think the fights or the smell should really factor in when deciding which pair to get. With girls, there is always the option of adding more, whereas boys have to be kept in pairs. Perhaps you could meet both pairs and decide on the day, go with your gut and who you bond with the most. That’s my very lengthy advice, anyway!
Edit: just to add in, i think boys definitely get a bad rep, I have no idea why though as my two are the most loveliest, cuddliest, inquisitive little things that I could ask for.
I’m aware of the current lockdown situation but was using the current time to prepare for new pets
