Narrowed it down to the Unicomp Classic or the Leopold FC500R.
Both fine keyboards, but with the FC500R you get four choices of switch (blue, brown, black and red) and none of those is like buckling spring. Not even MX blue: even though it's tactile & clicky -- and so is buckling spring -- the key weight and general feel are very different. Some people love blues to death; others love buckling spring and hate cherries.
So you're asking about two very different alternatives, and asking us to tell you which you would prefer. Given that it's such a personal thing I think there are limits to the quality of advice we can give, but here goes...
If you like a keyboard with a very firm, tactile feeling, go for the Unicomp first. You may love it or hate it, but it's not expensive and at least you've experienced the awesome phenomenon that is buckling spring.
If you prefer a keyboard with a medium to light feel, consider the Leopold with blues or browns. Lots of people say they like browns best. Reds are good too: superb for gaming, and very comfortable for typing if you like a light feel and you've got the patience to get used to them (touch typing on reds accurately isn't easy).
but I am concerned about the noise it may make,
The noise issue will be just as bad with MX blue, perhaps worse. It makes a higher pitched, crispier clicking noise which some people find more irritating than buckling spring.