There’s a lot of excitement in the music industry around startup Topspin Media, which is promising to reinvent digital music marketing. Unsurprisingly, its rivals are kicking back against the hype. For example, Echo CEO Mark Montgomery has written an open letter on the company’s blog to Bob Lefsetz, who praised Topspin. In it, Montgomery claims that Echo has been doing what Topspin talks about for five years, and “we have chosen to tell our story thru the success of our clients, rather than shouting our name from the rooftop… end of the day, it’s not about us, it’s about the artists we represent.” He also says Echo has served 125 million pages to its artist clients’ fans in the last month, and served up 20 terabytes of files (including digital downloads). Let battle commence!