Been using Koolex Cleaners (at their South End location) for several years.

They are pretty reliable (although they did mangle one of my wife's dresses once) and are much cheaper than some of the other downtown dry cleaners.

Koolex is located at the end of the stripmall with Blockbuster and Little Caesar's (across from Sobey's). I don't get a lot of clothes dry-cleaned, but this is always the place I go. You can get same-day service if you bring your clothes in early in the morning, the prices are good, and the staff are always friendly too. It's a convenient location because you can drop off/pick up when doing other errands in the neighbourhood.