Can I add my 2 euro? This year will be number 14 for me in Assisi - I'm a director for international music festival in July. Yes, you can find tacky souvenir shops. Yes, it can be crowded. BUT! There are some beautiful and original things to buy like olive oil, balsamic vinegar (great shop for both directly across from Hotel Giotto); wonderful leather goods (very narrow shop on the left side as you are heading up the hill from the Basilica San Francesco); amazing art (keep going, you'll pass several studios that are well worth looking at). You are more than welcome to just "take a look" and you will be greeted by some very friendly people. The food in Assisi tends to be part of the Umbrian "slow cooking" menu. Lots of fresh vegetables, excellent meats, local wines and don't forget the gelato (proof that God wants us to smile).
Crowds? During the day, yes. At night, no. Of course there are the specific and special places you must visit in Assisi: the Basilica of San Francesco, Basilica of Santa Chiara, the Cathedral of San Rufino, Santa Maria Maggiore, Santa Maria Sopra Minerva. There are also a few museums that don't get the crowds but are filled with local history. Rocco Maggiore (the big castle on top of the mountain) is a nice get away. Hire a taxi and go up Mount Subasio for the views and the Hermitage (where St. Francis and the friars went for peace and quiet - it's still very peaceful and very quiet). I do these every year and have yet to tire of them. Go down the mountain and see San Damiano and (lower) Santa Maria degl' Angeli. The view up the mountain to the medieval city of Assisi is stunning. At night the city will be pretty much yours. The tourists will be mostly gone. The Piazza Commune is a wonderful place to sit, have a drink, enjoy the people watching. If young pilgrims are in town there may be singing and dancing - a lot more enjoyable than you may think!
I love Assisi. Every year I'm joined by wonderful singers and instrumentalists from major symphonies and opera houses for nearly 3 week. Probably 90% of the musicians return every year. We must be doing something right - or we have found the perfect location to relax, study, rehearse and perform nearly 20 concerts in 2 weeks. Some of us call Assisi 'paradise'. I always say 'Assisi is where I like me.'
Hotel? We stay at the Hotel Sole which I love and it has a wonderful restaurant. I've also heard wonderful things about the Dei Priori, Giotto, and Panoramic. Sorry, don't know the convents but I imagine they will be very special in their own way!