I went through a phase where I updated every one of my receivers via a telnet session for a good 6 months, It was just easier and quicker to fire up a telnet session, issue the update command and let it do it's own thing.
It is good from a testing standpoint to try all ways however, especially if like me you have multiple receivers to update. so now when I have the time I alternate which receivers get updated by USB, telnet, Couch flash or online update just to make sure all methods work as they should.