Audio Friends Don't Let Audio Friends ...

I would give my opinion if asked. If the person is unsure about his choice and is seeking validation in what others think then perhaps he needs to hear the painful truth. But if the person is enjoying his latest upgrade, why ruin it for him? Also, the choice of words would depend on how close of a friend the person is. My best audio buddy and I have polarized opinions on what type of amplification we prefer (among other things) but that doesn't stop us from supporting one another and enjoying each other's system.

The Truth shall set you free...

Let me turn this around. I had a good friend over last year who I had not seen in years. Thing is, I DO value his opinion in audio since it is one of the things that we have in common. So, after listening to my set up, I simply ask what he thinks of it. 'Sounds good." As in what, sounds good? No more to say than that? He didn't give me a straight answer, so I shot him. Well, I didn't shoot him, but I talked about it. This guy who is my friend has no real observation about what he heard? I LIVE in the audiophile desert of the USA. I wouldn't ask anybody around here what they think of my 'waste of time.'

Tell him nicely and then whip out a pair of magical cables and convince him that that will fix everything

If they are happy, then keep it to yourself, why deflate the bubble....

There is a possibility the situation is actually the reverse and friend is not appreciating the improvement.