"High price" is relative to time. The price surely seemed high at $30 in 2011, and at $1000 in 2013. If you believe that a single BTC will be worth millions of dollars someday -- as many of us do -- then $8400 is quite cheap. In that sense, it's definitely a good investment.
That said, you need to be prepared for the volatility. I think we could definitely see prices like $5000 or lower in the coming months. I prefer to trade the volatility. If I were investing for the long term, I'd probably wait out the market a bit.