From my interpretation of "common wisdom"...
The most robust/reliable rewrite format.
The least supported (both in write and even reading)
More expensive for media
http://en.wikipedia.org/wiki/DVD-RAM - a very detailed description
My understanding (I could be wrong) is that DVD-RAM is TRACKED (like a hard disk) rather than spiral, so it does have random access capability for bothe reading and writing.
It can't hurt to have a "triple format" drive like the LG, so long as you check the reviews and find the performnce acceptable on the more mainstream media types, as unless you also have a DVD-ROM drive with DVD-RAM reading, the use of DVD-RAM media will be confined soley to the writer.
One thing I'd like to see, is a drive that supports DVD-MRW mode (Mount Rainier) - a promising, and in the end, reasonably well supported CD-RW feature that put a large chunk of packet write error handling in the hands of the drive, but a miserable lack of support in DVD writers!