You're probably not going to look at the 2013 BMW 1-Series for flat-out practicality--although if you're weighing it against a traditional sports car, it may impress as a better daily driver.
Whichever version of the 1-Series you're looking at, it's quite comfortable and easy to use--provided you're not thinking about using the back seat too much. Laid out like 2+2s more than true four-seaters, the 1-Series Coupe and Convertible models offer plenty of comfort up front for adults, with the rear seat best left to kids.
The trunk itself is fairly roomy, even in convertible models, while a pass-through split-folding rear seat offers more cargo space for longer or larger items.
Considering that the 1-Series is the low-priced entry point into BMW's lineup, its interior materials are quite impressive and build quality is strong. They're not quite up to the standards of the latest 3-Series and 5-Series in most respects. The one thing that's noticeable is that trims and plastics are slightly lower-grade. Cabin noise is low, with wind and road noise well-controlled, even in the convertible--so that stands as a big benefit over a number of other performance cars.
In general, on-the-road comfort is good, but it does depend on some of the performance options chosen. The low-profile tires with larger 17- or 18-inch wheels--as used in the 135is as well, or with the M Sport package--can create more ride harshness.