I agree too. I was just revisiting this stock. I owned it in 2006/07, Bought around $40 and sold at $58. I was very lucky not to own it going into 08/09. A very attractive entry point would be 5x EV/EBITDA, which worked out a bit below $20 a few years ago -- but now, that works out at around $10. They have added debt increasing the EV, but the acquisitions haven't added much EBITDA. Clearly they have overpaid for recent acquisitions. An entry point with no margin of safety would be around 10x EV/EBITDA or around $38 -- which I could say is fair value -- so it some 70-80% overpriced.
It could be a good short. However, I think shorting IWO (Russell Growth Index) of which MTN is a small part might be a safer bet. A lot of small-cap growth stocks are overpriced. I'm not a fan of shorting. I just wish everything would get a lot cheaper as there is literally nothing attractive to buy -- stocks or bonds.