I went there with my parents today for my birthday; I had been in the mood for something Balkan. We ate at 7:00; there was only one other table in use (probably a good thing for my dad, who doesn't really like eating in crowded places). I was the only one interested in the Russian salad/boiled egg portion of the appetizer, but everyone enjoyed the liver pate. I agree with the previous poster that the cheese spread was extremely bland by itself, though mixing it with the liver pate resulted in something tasty. The soup was an extremely good chicken soup.
I had cevapcici and mucalicka (thanks to Rich4 and Mike G. for recommending the latter); my dad had mucalicka and my mom had the pork kabob (whose name I forget). Everybody was happy with their food. The texture of the cevapcici was a bit different than I remembered from the last time I had them (somewhere else), which must have been at least 20 years ago. The mucalicka was absolutely delicious; I was surprised it was so rich given its ingredients (the server told me that the sauce was simply the juice from the pork); however I concentrated on the cevapcici since I thought the mucalicka would probably reheat better (it struck me as the sort of dish that might be even better the next day).
For dessert, I had the walnut crepe and my parents each had apple strudel. The crepe was really more like a savory crepe than a sweet one; not quite what I was expecting but very good nonetheless. The strudel was also not particularly sweet (neither of my parents are terribly into sweets) and had a bread-pudding like texture.
The service was quite efficient (but then again, the place was hardly crowded). The tab with tax and tip came to around $80 (nobody had any drinks), a little bit high because I ordered two entrees and the desserts were fairly pricy (the crepes were $3.50 and the strudel were $4.50 each).
Simplon's definitely for carnivores only; just about all the entrees are based on veal, pork, or beef. Sweet-lovers should skip the desserts and run over to Taste of Heaven, Zephyr or even Margie's afterwards.
Parking in the neighborhood was quite scarce at 7:00 on a Tuesay night (I wound up parking in front of Spoon Thai, which I have yet to visit); if I were going there on the weekend, I'd definitely take the Brown Line for at least the last leg of the trip.