Sadly, I just can't recommend this phone. While the hardware is generally good (despite poor camera and famously loose headphone jack), the support from Motorola themselves leaves Android novices and experts totally stranded.
Given the company's open disregard for keeping the version of Android updated on their phones, you are virtually guaranteed that any Milestone you buy will be out of date (and not just a little).
This is not limited to the Milestone, but to all Motorola phones at the moment.
It is a crying shame, but HTC, Samsung and LG are all far out-gunning this formerly mighty company. All of my family and friends have bought these brands over Motorola, based on my recommendation and they have been delighted with the speed of updates and support from the companies.
If I can editorialise for a moment - I fear Motorola's former financial issues have meant that they are cutting corners on their software support. This ruins the customer's experience with the phone. Considering the length of most contracts for phones, a Milestone would be an unwise buy as it is already looking at the end of its support life from Motorola.