The biggest issue I've had with tech in the classroom is ...
... the curiosity and ease that led you to read this.
In our digital world, diversive curiosity is constantly stimulated by ever-present streams of texts, tweets, etc. that stimulate our hunger for novelty. In the process, our capacity for the slow, difficult, and frustrating process of gathering knowledge may be deteriorating. - Ian Leslie in Curious
That process may include a class discussion and conversation, students going to a text to find a relevant passage, or even making a correction to their own work to solve a problem. That's not something I want to see deteriorating in my classroom.
Easy and constant distraction is the biggest negative factor in using technology in my classroom. I've heard the same from colleagues as well. It took one new faculty member less than one semester to go from a computer savvy technology-in-the-classroom enthusiast to a "near luddite."
That's totally understandable. Technology in the classroom, with its hidden screens and plethora of distractions, makes even the most veteran teacher a first year educator initially. I know not every minute (every second?) of every class period is going to be so engaging and interesting for every student that someone is not going to be tempted by a distraction. Although, I certainly won't stop trying. Having technology so easily accessible makes it very easy to act on that temptation.
Even so, technology definitely has a place for students in my classroom. Right now it's used for daily assessments to check for understanding, to read texts, and for some note taking. I've tried to strike a balance between effective classroom technology use (for both students and me) and "old fashioned" face to face time. It's like the balance it takes to stand on a ball - it requires constant and continual practice and attention.