This was around July 2010-ish.
The development environment: Sucked. Eclipse with some rubbish plugins that didn't work all the time.
Each change in the UI, I had to compile, publish to my BB device (which took about 20 minutes each time) and see how it ran there because the simulator was nowhere near to the actual representation on the phone.
Using Java to make BB apps wasn't so bad, I mean, I was only used to C# at that point, and the transition wasn't that painful. It was the god damn awful developer tools.
I wouldn't go back to making Blackberry apps ever again; I value my happiness much more these days and I can afford to pick and choose my jobs.
I wonder if they have made things easier this iteration. It's been 2 years since I've seen things in the ecosystem after all.
My absolute favorite platform to make Mobile apps is Windows Phone 7 (I hear 8 is pretty much the same). You just can match the developer tools for it. It's so simple.