I understand you, I also give not my money to brands which aren´t friendly to me.
I also like 256GB-SSDs more than 240GB, but the amount is getting smaller. In the past it were mostly the SF-driven drives, but now there are also Marvell and Phison. LAMD-drives have mostly also only 240GB, exceptions are the Neutron 256GB with Hynix-NAND and the Super Talent Super Nova III
One of the cheapest 256GB-drives is the Transcend SSD340 with JMB-controller. But I´m not sure about the quality. It came with a low price at the beginning and then the price dropped before it was avaible.
Do you know whether you get a Plextor M6S for testing when it´s avaible?
Benq DW 1640, LG GH-20N, Pioneer BDR-208
Crucial M4, Sandisk SSD, Plextor M5S, Sandisk Ultra Plus, OCZ Petrol 256GB