Ahh yes of course, giving my personal opinion on a new piece of software means I must be a right boring loser because I don't think it's very good? Nice logic.
That sounds more like your apps crashing, in which case it would be the app makers fault, does it only happen in a few apps or in all of them? It might help if they're crashing due to an issue with iOS but this sounds unlikely, more likely upgrading would have no impact on particular apps...
Well, I've actually used it, on the phone he will be using it on and my experience was poor compared to the current software, so I would recommend him not to upgrade.
Additionally I installed it on my iphone 5, which wasn't laggy but is still pig ugly, barely a new feature to speak of but they...