They don't necessarily have the biggest variety, exactly what I'm looking for, or rock-bottom prices, but they're the best place I've found to shop for bike parts and accessories.
I've given up trying to support small, indpendent shops because I have been met time and again with lazy, arrogant or incompetent service.
It might be a bit hard at times to flag down an employee at Stadler but when you do, they're friendly and helpful.
An absolutely massive bike shop with every possible kind of Fahrrad you could imagine from budget bikes, right through to EUR10K racing bikes.
There is a huge selection of accessories and even a indoor track where you can try out your bike before buying.
Another advantage over a smaller shop is that because they have so many bikes, there are also a lot of good deals going. I got a EUR600 crossrad half price.
After years of buying and building bikes, I've always been of the mind that you should support the smaller, independent bike shops.
But recently, the smaller bike shops in Berlin have just been getting worse and worse. I've had incompetent and patronising advice, disinterested and condescending service and, worst of all, after selling me the bike or equipment had zero commitment to making me a happy (and returning) customer.
So I tried Stadler. And was really impressed. They have great, very competitive prices, but most importantly, they have proved time and time again to have an excellent, customer-focused attitude - always assuming the customer is king and as a result I've returned many times to buy bikes and equipment. They've been flexible and understanding and efficient.
I'd give them 5 stars (but dropped one star just due to the slightly limited range of manufacturers supported).