You know... it's funny but I do see the difference between an I and a G! Not from the top, no. And certainly Tiffany I's are low-colour I's. The thing is though at this size and in this setting, when you look at it from the side it's held up to the light so much and there is so much diamond "glass" visible that you do get a REALLY good look at the colour from the side, and that's where you see it if you're particularly sensitive.
Plus I have to admit I have a slight mind clean thing about not going to the "lowest" Tiffany carries. I know it's super snobby and will cost me size... but for some reason while I don't need or lust after NEARLY their best (DEF), I don't have their "worst" either! It's a mind clean thing I guess. I've seen a lot of people here suggest I go up to VVS2 or VS1 if I can swing it and to me I don't mind so much being VS2 at ALL, so I think it's really personal in the end. I quite enjoy the game of finding your own personal sweet spot actually!
... before they carried SI1's I was happy with VS2's and still am, even though that's technically their "lowest" - but that's because I really can't see the flaws in my own VS2. I CAN see colour... I seem to be pretty sensitive. Like I said with the G I don't see it unless it's next to a D... but when I look at the I from the side with anything resembling a white background, I see the warmth and it bugs me. BELIEVE me it's tempting! It was a STUNNING stone ... but I know I'd regret it!
I think it's a "mind clean" thing. Certainly no, anyone who admired your ring at lunch when it's not perfectly clean and didn't have a white BG behind it wouldn't be able to tell the difference between a VVS1 and a VS2 or a G and an I.

So it's definitely a better deal! I just see more colour than some I guess. Even the SA's at Tiffany's were impressed with my eye for colour, I can arrange them by colour pretty accurately when looking at a few together.