I've had this thing for more than five years. It's awesome and I've recorded tons of stuff with it, recently a LP for my band, SHOOM, was all recorded on that white marvel. Check it at www.shoom.band
R16 is very useful, full of features and well designed. However, the thing that you should know is that ZOOM is a cheap brand and R16 is a fragile plastic box with low quality parts. Mine already has most of its input jacks not working with XLR cables, the gain knobs inject crackle noises etc.
The other major design limitations are 1. it records in 16bit format, no way to get 24 or higher. Some sound engineers cringe over that. 2. phantom power on two channels only 3. effects available only on channel 1
Still there's no other product on the market that does what R16 does for $300, so I do recommend it.
I read a load of reviews before I bought this and it does so much so well. I tend you use it as and interface and control service which is does well. I've read that recording on it rather than through it is also very good.