IMO DM7 was the best DM to come out. Especially for the price. You are not getting much more with the subsequent years. And weight isn't significant between the DM7-DM9. Remember that the DM7 was actually lighter than the DM8. They all shoot the same once you tune them correctly.
When you are considering another gun in the Eclipse lineup consider an 07 or 08 ego. The 08 are already dropping in price. You can already find them for 500. That only means that the 07's will be dropping even more, quite possibly into the sub-400 range. I would definitely consider either one of those above an Etek2, which I personally hold on the same level as a PMR, while some may say differently that is just my opinion.
Hope that helps.