I just recently priced out 9kg machines or close to it. Miele was the CHEAPEST compared to Electrolux (Wascomat) or Speed Queen. I think the difference is Miele sells direct on most of their commercial units. Call Princeton and ask to speak to sales. Don't go through a dealer. They will discount 10-25% depending on the model and what they have in inventory. I was SHOCKED. My guess is they don't pay any dealer fees this way.
Do you need an onboard heater? That costs EXTRA with electrolux and speed queen. It is included with Miele.
Here are some numbers for you:
Miele PW-5105 (10kg-25lbs) $6600
Speed Queen SY25 (10kg-25lb) $7000 Electric Heater extra $400
I didn't write down the electrolux numbers as they were higher than both of the others. Electrolux has their new pro 6000 line just rolling out. They are a LOT better than the older 5000 line. Both in features and capability. They will be the first line with built-in remote monitoring of the devices. Run diagnostics, see energy and water use by machine, alerted by smart phone for errors, process chemical empty, etc.
For Dryers we got pricing on the following:
Miele PT8303 $5400 25-35lb range Electric (Need three phase)
Miele PT7186 $3500 20lb range (240v Single Phase)
Speed Queen is almost all gas dryers and we didn't have a gas line plumbed. We were quoted $4200 on the dryer and that was WITHOUT residual moisture control. meaning no sensor dry.
Keep in mind that anything over about an 8KG machine (17.5lbs) will NOT come with a drain pump that most residential models will have. They almost all will have a dump valve so you will need a floor drain to plumb the washer into.
If it were me, I would go Miele. Call Princeton and find out where Miele has their own techs in your area and how far they would need to come. The techs service both residential and pro models (despite what others may tell you). Miele normally will charge mileage for distance beyond 50 miles from where the tech is stationed. Not really a deal breaker, but if it's 250 miles then you might have to re-think Miele.
My 2nd choice would be Electrolux. They are similar quality to Miele on their professional line. You might be able to get better pricing from a dealer in your area. In the USA, electrolux uses LaundryLux (a distributor) to get equipment to local dealers. So there is markup for both LaundryLux and the local dealer. The only upside I can see is that there are more dealers. The downside may be that service will only be as good as the local dealer.
For your B&B electrolux has the MyPro range. They are 18-20lb machines that are in-between the residential and profesisonal models for build quality. Designed for 1-3 loads per day. Have a drain pump option or dump valve. Call the dealer and ask about the 6000 model line washer and dryers. They really look nice and I think they will really give Miele a run for their money.
Speed Queen looks REALLY old compared to a lot of what Miele and Electrolux have on the market. Speed Queen will say they are built like a tank, etc., but they really aren't bringing their models into the 21st century. Miele will have the highest water extraction G-Force rating, following closely by Electrolux. Speed Queen is in distant third. They leave a LOT more residual moisture in the wash for the dryer to deal with. More $$$$ in operating costs.
If I were running a B&B and doing the laundry myself, I would REALLY want that smart phone app to let me know when loads are done. I can then start washer and dryer and let the thing "beep" me when I need to come back and move something. It would also be nice to know how much water and energy is being used. It will help you to budget more accurately so you can bill your customers accordingly.
Hope that provided a little more information