I currently have the Lumia 635 but managed to get a used Lumia 920 on amazon for a low price. It seems that overall the Lumia 920 has more features than the 635 as it was a flagship when it was released. However, I am wondering if the 920 is going to be much slower than my current phone. The Lumia 920 has a full gig of ram but has only a dual core processor while the 635 has a quad core and a newer GPU. Also I noticed that the Lumia 920 does not have a removable battery. Does this mean that if the battery can no longer hold a charge for a while, the phone will be a brick and I would have to get another one or is there a place where they can service it and replace the battery for me. I currently have a 16 GB SD Card in my 635 which makes for a total storage of 24 GB. On the Lumia 920 there is an internal storage of 32 GB but there is no SD Card slot as on the Lumia 635 which would help me go well over 100 GB for storage if I wanted to. If you have the Lumia 920 has the 32 GB been enough for storage. I would have gotten the 735 but it is still not available in the US and too expensive.