Based on my experience my MIT SONY08D1 and DONYD11 from a spindle and a few 5pks, I would not recommend these for long term storage.
Burn quality is generally average at best, and bonding is mediocre. Sony media also got a "--" rating in C't magazine's accelerated aging tests (aka the worst possible).
Now, I'm not saying that Sony isn't capable of making good media, but instead that Daxon, who makes Sony's MIT media, isn't. If you can find any "Made in Japan" Sony media, DVD-R or DVD+R, you'll be in good shape.
Where are you located?