Overall, the city has fairly good infrastructure with an aboveground metro, the trendy and commercial Poblado (where I stayed) a variety of communities and metrocables to serve all the people who live in the favelas.
My stay was pleasant as I met some other travelers on the walking tour and had a cool Venezuelan lady in the same airbnb apartment with a glorious view. The apartment was nearby Parque Lleras where I got to see the more "gringo" clubs, bars, and prostitutes (legal). In spite of that, Parque Lleras was a safe and relaxing place to enjoy a shot of aguardiente, ron (rum that you can keep if you don't finish in some places-ones that you'll have to ask specifically about) or beer in public! Yes, you can drink in public in Colombia, small but simple liberty to enjoy.
Outside of exploring Medellin and its gorgeous women (quick note on this later), I took a overly long trip to Guatape for some grilled trout. This was an experience as I had to take a chivas bus (pick up random people all the time) next to this old school Colombian with a cat. When I arrived in Guatape, it was a decent spot that maybe wasn't worth the journey, but it was entertaining when I tried to get service and it took forever & we got skipped over. Myself and several other patrons left to find food elsewhere. As such, I did finally get that grilled trout with a glass of Milo (amazing chocolate milk). Overall, Guatape was decent even though I didn't climb La Piedra (which I hear takes little effort). If you have the time go, otherwise find other activities around Colombia.
Quick Note on the women of Medellin and Colombia in general. There is much said about the women here and all that is true for the following reasons. 1) Image is huge here, most advertisement is geared towards women who have a certain look(Medellin has the European descendants of Colombia), hair extensions, plastic surgery, makeup and a whole lot of glamorous outfits. 2) The women do double takes, the average woman in America may or may not even look at you at a bar because hey that's their life. I found Colombian women to look at me and even stare a couple of times. 3) Its generational, many times I found mom, grandma, and daughter all looking dressed to the nines.
Lastly, I would end off with a trip to Concordia, Zona Cafetera to see a coffee finca with a wide array of animals, coffee berries, how coffee was made and how the prices of coffee were determined. It was a truly great experience where I got a chance to purchase some coffee.
In the end, Medellin is wonderful, at first glance Bogota seemed cooler (Medellin was hot!), but Medellin functions extremely well as a city and I highly recommend it and the wonderful country it is in to everyone.