In general, yes, a 5 years old stroller, especially a better one like the Buffalo, should be totally ok. However, you need to check it beforehand - it always depends on how the original owners treated it, and so you should check for rust, a lot of loosenesses, damage, and so on. If all looks reasonable, the Bugaboo Buffalo should be, in my eyes, the higher quality choice - however, you should only go for it if you need something more all terrain. The ReSea is smaller, more compact, but also more urban - which, in a city and undemanding walks can be a bis positive. If you will need more terrain-capable pram though, go for the Buff.