I'm not familiar with the Samsung, but the Lite-On and LG work fine with Verbatim's 4x DVD-R DL media. Don't bother writing to them at 2x or whatever. Just burn them at 4x.
I haven't tested the Pioneer 216 yet, but I've been less than impressed with the 116's writing quality with DL media.
"Blu-ray is just a bag of hurt." - Steve Jobs