They will continue to get better. The DIY version will also get better. These ones are the future, since they already have an epoxy coat. You don't even need a glass pane on top of them.
and for the prebuilt ones, the prices for 320W panels are the same as 100W panels 5 years ago..still, I think that the most cost effective now are the 160-240W panels. Because Gauss' price curve :D
I will keep you updated since my system is not yet completed.