I'll compare it to my old VX Nano mouse that I prefer for 2 reasons. The VX Nano has 2 R3 batteries (AAA) while the M505 mouse has 2 AA batteries so it seems to me that the M505 is heavier but there is no big difference. Then on the VX Nano wheel is silent while the M505 wheel is noisy, it's really unpleasant. The positive point of the M505 is battery life, which seems logical given that they are larger. When I put the battery inside he posted 450 days, it's a very good battery life compared to the VX Nano. If the horrible noise of the wheel do not mind I suggest you buy it, for the rest it is a very good mouse has a very affordable price.