I love Boom, it is a good old fashioned drum sequencer and is so easy to use.
It comes with some great kits, like the 909 and 808 but there are some other versatile kits suitable for edgy Hip Hop or clubby Electro. These can be mix and matched if you know how but this feature is hidden so I will show you.
Additionally, I really like the Swing on Boom that really adds a groove to the most mechanical sounds. The step sequencer is easy to use and I like the velocity selection (though I do need specs to see it).
I think with Boom, Hybrid and Xpand2 you can make any sort of tune regardless of style. The team at Air Instruments did that good of a job with them. I don't particularly think spending money on third party plugs is wise until you have checked these three tools out.
They are that good.