I got the 1750 Seido battery a week ago. It's great, has increased battery life by my measurements 30-35% and it fits exactly like the OEM Eris battery....the back is tight with no gaps.
ie: Old battery=1 and 1/2 hour on phone, 30 min in browser, 30 texts, and 4-5 emails phone lasted from 9 AM to 6 PM mobile always on, wifi off, bluetooth on and off. With 1750 battery my phone has ~30% battery left by 6 PM. Gives me more Eris play time during the the day if I want
Now that I turn mobile off for most of the day on only turn on via toggle switch on homescreen to surf or get emails, my phone last 2 full days without a charge...this of course happened after 3-4 days of battery break in