I posted to this last night. The short of it was:

If you looking to buy the 2500 (street ~$500) and are maily watching movies, the 990 will not give you twice the performance for twice the price.

If you already have the 2500 and are wondering if it is worth ~$500 to upgrade to the 990 as you should be able to sell the 2500 for about $500 (I did several weeks back)...to me, yes it is worth it. Movies are a good deal better though not twice as good. 2-channel music is easily twice as good and then some. These are just my opinions, so take them with a grain of salt.