For the small cost, I would suggest getting an on line subscription to Consumer Reports. They have a lot of information on washing machines and how they compare.

For an upstairs location near bedrooms I would choose a model that rates well and in particular for noise and vibration. CR tests for both. In general top load washers have less vibration than front load. There are dozens of each type rated by CR. Most of the top loads are rated excellent for vibration. A few of these, like LG and Samsung are rated very good for noise. None are rated excellent.

Of the front loads, only Samsung is rated excellent for vibration. Many are rated VG for noise, but none excellent.

LG and Samsung have the best ratings for frequency of repair. If it were me I would select one of these two brands that rates well and fits the budget. Probably the Samsung if it must be a front load, and the LG if a top load.

No Miele washers are rated by CR. No idea why, but guessing in the past CR has rated Miele products poorly -- expensive, break often, and expensive to repair. Perhaps they have gotten tired of lawsuits from Miele and just stopped rating them?? Don't know.

I have a laundry room on the second floor, and about 6 years ago I replaced a top-load washer (Amana, I think) with a front-load LG. Before I replaced the unit, I had read a lot about vibration and noise from the front-load units.

I have never had a problem with vibration/noise. I've also never had to call for a repair. I don't know if my research paid off and LG is unusally good or if I just got lucky.

When I was visiting showrooms and asking about vibration, most of them told me to put down a rubber mat and that would help considerable. You should definitly ask your appliance showroom staff and your installer to see if there are tricks of the trade.

Are you talking Miele FLs? I have a much-praised Samsung FL and wish I'd just gone for a Speed Queen TL. It pipes cute little sea shanties when the cycle is done. But I certainly hear it up in the kitchen when its spinning, and that's with it down the basement on a concrete floor. Can't imagine it inside an old house.

Also, it depends how you like to do laundry. In our old apartment, with an old TL in our unit, I did all the laundry. I didn't mind, and I did it the way I cook. Little of this, little of that, as I thought the load needed. It was easy to add Borax or bleach or vinegar or whatever the clothes required. FLs are mincing and pinch nosed about all that stuff. Too complicated for me. Luckily I hate our basement and won't do the laundry anymore anyway.

I have been researching this as well - I am converting a second story bathroom in an older house into a laundry room. Because I want to stack mine, I was specifically looking for sets where doors would/could hinge on the same side. I have decided on Electrolux 60 series because of that feature and their positive reviews. For what it's worth, Electrolux bills these as having a "perfect balance" system making them ideal for upstairs installation, but since I haven't installed them yet I can't comment. Based on my experience, a lot of shaking with any unit comes from improper installation. I am asking my plumber and contractor to set ours up with a pan and floor drain, and we are creating a reinforced platform for the units to sit on. I have an LG W/D in a closet off of our dining room in our summer house and they are very quiet and don't shake, so I am not particularly worried about having a quiet set in an upstairs room. Typing that last sentence is just asking for trouble from the appliance gods. Oh well.

If at all possible I would opt for a TOP loader every time.

I think the basic issue with a washer is the unbalanced load. When an unbalanced load spins it creates some significant cyclic forces. With a front load the forces act downward through the floor, and because you must have contact with the floor it transmits a lot of the energy down. With a top load the forces cause the machine to move side to side. If it doesn't hit anything, the top load does not transfer much of that energy away from the machine.

We have friends that put a front load in their second floor right above the dining area. When you are in the floor below, you certain know when the load is unbalanced.

I put in a second floor laundry in the last remodel. For better or for worse, I had none of these considerations in mind. Just be wary of the load a washer puts in your drain stack, especially in an older home...

We have a second floor laundry room with 6yr old LG front loader. It can vibrate and cause dishes to vibrate in the kitchen below. It may be exaggerated by the fact that there is an I beam just below, so it may transfer the vibrations more so than wood. So you may want to consider how your house is constructed. Will the room be near load bearing wall?

We have a second floor laundry room. When I mentioned this to the local appliance specialist shop, they immediately changed their recommendation to Electrolux (which tallied with the research that I did on the subject).
So we have a steel grey IQ Touch EIFLS60J washer and EIMED60J.
They seem to be pretty quiet - not noticed vibration or shaking. We did have water under the washer but it has not happened again and it is unclear whether this was from the washer, the line or the Purewash system we also had installed (that definitely had a leak).