I've decided to go with an SSD refurb and am torn between the 1.6 and 1.8 SSD model. The 1.8 is an extra $100, but it's $100 which may be over my budget and I'm not sure if I'll really notice a difference. The reason I want the 1.8 is because I'm coming from a 2.0 MB and 1.8 doesn't seem as bad as downgrading to a 1.6. HELP! Is the 1.8 vs. the 1.6 worth it????