Are they similar, or is one more quintessential than another?
Well, the quintessential one was in Sauchiehall Street but that's gone (building is being restored.) The Willow Tea Rooms website suggests Buchanan Street has been there longer, while the branch in Watt Brothers is almost brand new. But they're both somewhat ersatz.
Here's an article that explains the situation:
If you are interested in Charles Rene Macintosh you might want to check out Hill House, in nearby Helensburgh on the River Clyde.
What a bummer! Now I'll never see the original.
Trust me, the original Willow Tea Room was not all that exciting. Hill House, though.....
You should really try to get out there. I liked it a lot more than I expected to.
In addition to the Hill House , easily reached by train from Glasgow Queen Street - line to Helensburgh Upper , then a few blocks walk , The House for an Art Lover in Bellahouston Park will knock your eyes out ! This was a design created for an architectural competition in 1901 but not built until 1996 , a five minute train ride from Glasgow Central to Dumbreck , ten minute walk to the house .http://www.houseforanartlover.co.uk/about/history-of-the-house This fine 45 minute documentary about Mackintosh and his wife , Margaret MacDonald , will whet your appetite . Once asked about Margaret , Mackintosh responded - " I had talent , Margaret had genius " https://youtu.be/LNrV6vbu4os
We were last in Glasgow in the Autumn of 2014 , shortly after the trust took over the building . According to the article posted above , a full restoration was to be undertaken . Nearly three years later , I would assume it has been completed , and a visit to Sauchiehall Street would be sensible . As far as your comment that you would not be able to see the original , allow me to comment . In 1996 , there was a major retrospective of Mackintosh's work at the Metropolitan Museum of Art in NYC . One of the major displays was a recreation of The Salon Deluxe from the Sauchiehall Street location . It was perfect in every detail . When I first saw the original in 2010 , I was struck in that it was virtually indistinguishable from the reproduction , such is the care that great art institutions take in matters such as this . If the room is now recreated in the original building , you will " really " get to see it . There was recently a thread about the " original versus reproduction " issue on the website , from my remarks , you can judge my perspective . Another good example is also a short daytrip from Glasgow - Stirling Castle , and the fine restoration of the Renaissance Palace there , which took fourteen years . If you want more detail about this , let me know .
The Sauchiehall location is still closed, according to friends who were in Glasgow recently.
If you are interested in the works of CRM you should visit Scotland Street School Museum. http://www.glasgowlife.org.uk/museums/scotland-street/pages/default.aspx
Confirming Nancy's post above , the Sauchiehall Street location is , indeed , closed , but will reopen at some point in 2018
I was in Glasgow in September 2016. When it came to Mackintosh sights, The Glasgow School of Art was completely obscured by scaffolding, and as you've been told, the Willow Tea Room on Sauchiehall Street was under construction. But, the Mackintosh house at the Hunterian was very interesting, and the House For An Art Lover was a 5-star wow (don't miss it!).
Details of my trip are here: https://community.ricksteves.com/travel-forum/trip-reports/uk-trip-report-glasgow-manchester-liverpool-in-september-2016
I went to two different Willow Tea Rooms during two different trips to Glasgow a few years back. One was over a jewelry store and one was up a flight of probably 45 steps. On crutches, that was a trek. Had my first Haggis there. It came with Balmoral sauce. It was not bad. I would eat it again.
Regards,
John