So, what footwear to bring to Bonnaroo? This is actually pretty important, you'll do a lot of walking at 'roo. Your campsite could be a 20 min walk from Centeroo, there are 5 main stages, a handful of smaller ones, official vendors, Shakedown Street, etc.. A lot of places to be and your feet are your transportation. So, in no particular order.
Great sandals, very good for festivals. If I was only going to bring one pair of shoes to Bonnaroo, it would be my Tevas. They are light, comfortable, sturdy and have very good tread that doesn't slip in the mud. Your feet will get dirty, but honestly, so will the rest of you. Just remember to put sunscreen on the top of your feet.
Fine if it is dry, but bad choice if we get rain. They are comfortable but absolutely shite in the mud, which can very often look like this;
If you walk through mud in flip-flops; you put your foot down, it get sucked into the mud, you pull your foot up, the flip-flop gets stuck, it pulls loose, it flips mud up your back, repeat.
I've never worn them, a lot of people swear by them. They seem to work fine for festivals.
Sneakers (or trainers for the UK types)
They are OK (the above survived Woodstock '94). They can get waterlogged, that can get uncomfortable. Wear good socks.
My favorite shoes. If you like going barefoot these are great. If you have a pair you know how good these are. One word of caution, the KSO's (and any others with slick razor siped soles) will slip in the mud. Shouldn't be a problem with the knobblier soled ones.
Boots are great for when and if it rains. The past few years we've been lucky and the weather has been dry at 'roo. I still keep a good pair of waterproof hiking boots (and good socks) in my truck just in case we get another 40 day flood in Manchester.