Old Town is a bit misunderstood.
The sometimes-good but other-times not-so-great service, the sloppy presentation of the food and the not-so-large (by Australian standards) portions and the smokers are some aspects that seems to draw irk.
However consider this: if you were in KL and paying less than 10 Ringgit for the delicious dishes and drinks, you would not bother complaining. In fact you would probably come back and rave about how it was the best $3 (in AUD that is) meal.
But when customers are paying roughly $10-15 AUD for a meal, they expect a lot more than when it only cost them $3. Finer details like service, presentation, cleanliness and second hand smoke become much more important. But the point it, this place is not purporting to be a restaurant, think of it like your local takeaway shop and any complaints (except those relating to the quality of the food) will seem rather finicky.
Besides who else in Melbourne can serve me such an amazing Milo Dinosaur.