Potter trail was formed in 2012, they are the trailblazers, thus having more reviews from happy customers.
Potter tour formed 2017, and I love every last one of my reviewers from their eyebrows up.

Potter trail has won awards from Tripadvisor for a high number of good reviews.
I have 0.0 awards. Liking for Quidditch 100%. Don't get me started on Gobstones though. I'm the newer player, I have to fly a bit harder.

Potter trail is 75 minutes. Less walking arguably makes it better suited to those who are disabled, or who have a casual interest.
Potter tour has hosted 4½ hour activity tours a few times, for families on a pilgrimmage. My tours are longer, I like reviving the magic sure, but I love what Rowling's life has to teach.

Quill writing in the Elephant House on a Harry Potter tour
Quill writing thankyou letters to JK Rowling to leave in the Elephant house for an 18th birthday on a 4½ hour Potter activity tour

Potter trail is fun and Funny.
I hope to provide something useful, perhaps inspiring and worthy of spending more time on. I want to make memories, laughter is satisfactory.

Potter tour's longer tours take in many more sights.
However Potter trail includes the underpass inspiring the Dementor scene from the Order of the Phoenix, Favourit cafe and many ghost stories I don't. These are all good things.

Potter tour vs Potter Trail Google review
This was a wonderful surprise, my first review from someone who has been on both tours & I'm very grateful for it

According to Will, one of the Potter Trail guides, I have "nice robes".
Never has Sam been complimented by a wizard — like an equal!

Bless you master William. Master has nice robes too.

Compare Potter walking tours

All tours are jam packed with sights of gothic romance:

The Potter Tour Rowling's Edina Complete Potter
Time 2 hrs 2½ hrs 3½ hrs
The Tron Kirk
Kwidditch postbox
The Nor Loch
Old College
Nicolsons cafe
Surgeons Hall
McEwan Hall
The Grassmarket
Tom Riddle's grave
George Heriots
The Elephant House
Andrew Carnegie's library
Eddie 'Newt Scamander' Redmayne's cave
Victoria Street
Edinburgh Castle
The witches fountain
The Witchery
Riddle's court
Lady Stair's mansion house
The Royal Scottish Academy
The Balmoral Hotel
The Heart of Midlothian
Inside Old Parliament Hall
Rowling's Edinburgh Award
Book a Potter walking tour
The boy who lived and I team up to create an industry
Edinburgh Harry Potter bus tour City Sightseeing

Potter Bus Tours Review

Edinburgh doesn't have a dedicated 'Harry Potter bus tour', but Edinburgh Bus Tours run the well rated City Sight Seeing tour. This passes four locations of interest to Potter fans:

If you're really into Harry Potter Edinburgh's old town is compact, a walking tour inspired by the books is a first class experience. But this bus tour has a downstairs deck which is warmer, it's audio guided in 10 languages, it's one hour, so you'll have time to visit the Castle and Holyrood Palace and it's absolutely perfect for wheelchairs.

City Sightseeing Bus Tour