I wrote this on my other thread when someone asked me why I got a 0.78 Harry Winston ring when for that amount of money, DBF and I could have afforded a bigger stone.
I'm not all about a huge rock, since it would look silly on my hand and I'd prefer to have an engagement ring I can wear on a daily basis. For our budget we could have bought a 1.5+ carat the online diamond sites, but I didn't like what they had to offer.
For me it's not just about the name brand. I know everyone has their own feelings about designer diamonds and jewelry, since gems that are GIA graded can be found at Harry Winston or an independent down the street. DBF and I had a long discussion and we just felt that if we were going to drop money on something that lasts a lifetime, we want a brand that will be around for ideally a lifetime. Like a Chanel purse from 1950, this is hopefully an heirloom piece and if we give our grand kids a HW ring or a Tiffany ring, they can take their space car to a salon and get it resized or cleaned or just serviced for their needs. Bluenile might not exist at that point and you'd have to bring it to an independent.
My future sister in law was telling me how she hasn't worn her engagement ring for 6 years since her fingers swelled up during pregnancy. She said she's afraid of bringing it to somewhere dishonest where they'd mess with the ring, replacing diamonds, putting in white gold instead of platinum, etc. While the scenario is farfetched, she did say she wished she had a Tiffany ring so she could bring it any store and get it serviced without worry.
I know everyone can say they have an amazing trustworthy jeweler on speed dial, but my family doesn't and I don't want to use trial and error in finding a place with quality I can trust for one of the biggest purchases of my life. I figure the price markup for the 'name' buys peace of mind and insurance for the future.
So for your situation, are you truly happy with a 0.25? Im happy with a 0.78, I felt that was big enough for my proportions. If your desire for size trumps your desire for a name, then yes it's true no one can tell what brand it is once its on your finger. I suppose in the end, do you care more that people see a bigger rock on your finger or for you to tell them it's Tiffany? I think you have to examine your priorities on what's important to you.
Also have you called around Tiffany diamond consultants and see if you can get a slightly larger, lower quality stone within your budget? Tiffany 0.5 carats start at $4000 depending on the cut... Although proceed with caution because we saw a 0.53 D VVS1 Emerald solitaire that was more expensive than a 1.0 carat round brilliant they also had