I registered to purseforum just to reply to this post! My bf (now fiance
) were in the EXACT same position as you deciding between the HW micropave and the Tiffany Novo. The entire halo or not to halo, does the HW look like a cocktail ring or not, and the exclusivity of the HW vs Tiffany which is more common was thought of numerous times by me. In the end I just told him I'd be happy with either one as long as it had another criteria that was important to me and that was the cut style. I didn't want the crush iced style if I could avoid it and wanted broad chunky flashes, sparkle, fire, and all that other fun stuff instead.
You can't go wrong with either one. In my opinion the HW does NOT look like a cocktail ring at all. Its so feminine and delicate looking in person.
I'm biased and in the end the bf surprised me with the most beautiful Novo, better than I could ever imagine getting for myself, and for me I couldn't imagine getting the HW anymore.
I just stare at my ring and move my hand to watch the light bounce and sparkle! My brother started to make fun of me and call me Gollum (from Lord of the Rings) and I joked along with him and started saying it was 'my precious', made a funny face staring at it and stroked it a few times. hahaha. I know.. geeeky and creepy.
My advice would be to look at the GIA report of the HW and see if its a modified brilliant or a brilliant. I think the modified brilliant has the crushed Ice appearance, smaller specks of light basically, but still beautiful if you like that look. I love broad flashes of light and have gotten so many compliments on how blingy, sparkly, and blinding my ring is from random people. (Mines a square cushion - brilliant)
Really take a very very very good look at both diamonds and see which one you love the best. They're both gorgeous settings in my opinion. Whichever diamond catches your breath more is the one I'd go with.
As for the upgrade policy at Tiffanys, I believe if you want to eventually upgrade, you can only upgrade to double what you currently have or more, so if you got the 1.5 you couldn't get a 2.01 you'd have to go 3.0 or higher.
Good luck and I hope you will love and adore the ring you choose forever!