I know the maps can be got via this site, but for me ease of updating is a biggie. Not worries about how long it takes or having to have an sd card etc. I know that whatever is shiny and new today will date, and as new facilities become available people will upgrade, but you can buy a device with lifetime maps for less than the cost of the device without it and the additional subscription by shopping around.

Personally, I paid for the subscription for european mapping (as that's where I live) and use this site for the US map. Garmin lifetime maps I think is a decent (if slightly overpriced) deal as it's genuinely going to give you new maps for 2-3 years when it's time to buy a shiny new one anyway. Tomtom is similar price but limited to one year - poor value.