My engagement ring was from T&C and I love every bit of it.
I think every brand will have its horror stories, loose fittings, lousy engraving etc etc.
But I grew up wanting a Tiffany, yes, I got all hyped up into 'the little blue box' marketing. But hey, it's my choice, I'm wearing the ring and not other people.
And my boyfriend, knowing me, he knew that I would rather settle for a smaller Tiffany ring than a bigger one at local jewellers, got me the Tiffany ring.
A lot of people have commented we're foolish as we can get a bigger ring with better specifications at other places. But my dream has always been the little blue box. And also, we've checked out other jewellers and my heart was still set on Tiffany.
After all, it's about giving the girl what she wants rather that what you think she should have.
I may be biased but for say, Tiffany's G or I colour, they are as white as can be and beat local jewellers' D or E colours. And even their clarity grading VS2 beats local jewellers' VVS1. Tiffany's labs are well known for their strict grading.
It depends on your own preferences. If you rather have a bigger ring for the same amount of money, then local jewellers are for you. But if you don't mind getting a smaller ring, then get Tiffany or Cartier or some branded jewellers, if you really want it.
Don't let what other peoples comments decide your choice because ultimately YOU are the one wearing the ring and only YOU can decide if it's worth it.