I have been here numerous times and it remains my favourite location for breakfast in Berlin. They have a good selection of breakfast options - including vegetarian options and also smaller plates with croissants and jams etc., but the draw for me is their bigger breakfasts including boiled eggs, ham, cheese, wurst, fruit, bread, it seems to have everything! Their prices are reasonable and it is the kind of place you can sit for 2 hours enjoying your morning without being rushed off. I am still somewhat confused as to whether they offer table service or not - I have been there on occasions and been asked to order at the counter, and other times have had my order taken from my seat. Maybe just something to be aware of - if it seems like they are ignoring you when you arrive this is not the case and maybe you are confused like me :) They also have excellent drinks - fresh squeezed orange juice (which you can see them squeezing at the counter!), coffee and hot chocolate are all great. They have a nice dessert/bakery selection too. In the summer they open up the doors and you can sit outside, and in winter it makes for a cosy place to warm up, it's perfect any time of year.
I go here most days during the week for coffee. It's cheap, strong, and never takes too long even when busy (which it often is). I've tried the sandwiches for lunch, and the chocolate brownies on a couple of occasions and the food is always fresh and delicious. Although I've not yet tried it, the brunch looks good too and the place has free wifi, and newspapers to read. Can't go wrong!