Some people on here don’t seem to understand the math that’s going on, so I’m going to make it very simple.
It’s April 11, 2014.  You invest in 1000 kh/s, costing you 1.55 btc. 
4/11   .0064 btc   4/12   .0070 btc   4/13   .0063 btc   4/14   .0055 btc
4/15   .0067 btc   4/16   .0073 btc   4/17   .0075 btc   4/18   .0074 btc
4/19   .0071 btc   4/20   .0075 btc   4/21   .0071 btc   4/22   .0108 btc
4/23   .0073 btc   4/24   .0074 btc   4/25   .0071 btc   4/26   .0057 btc
4/27   .0063 btc   4/28   .0057 btc   4/29   .0064 btc   4/30   .0055 btc
5/1   .0048 btc   5/2   .0042 btc   5/3   .0041 btc   5/4   .0041 btc
5/5   .0043 btc   5/6   .0049 btc   5/7   .0049 btc   5/8   .0047 btc
5/9   .0041 btc   5/10   .0042 btc   5/11   .0041 btc   5/12   .0041 btc
5/13   .0043 btc   5/14   .0041 btc   5/15   .0040 btc   5/16   .0037 btc
5/17   .0037 btc   5/18   .0037 btc   5/19   .0037 btc   5/20   .0037 btc
5/21   .0040 btc   5/22   .0040 btc   5/23   .0038 btc   5/24   .0037 btc
5/25   .0036 btc   5/26   .0039 btc   5/27   .0037 btc   5/28   .0033 btc
5/29   .0032 btc   5/30   .0031 btc   5/31   .0029 btc   6/1   .0028 btc
6/2   .0025 btc   6/3   .0023 btc   6/4   .0022 btc   6/5   .0022 btc
6/6   .0021 btc   6/7   .0020 btc   6/8   .0020 btc   6/9   .0019 btc
6/10   .0020 btc   6/11   .0019 btc   6/12   .0019 btc   6/13   .0020 btc
6/14   .0020 btc   6/15   .0021 btc   6/16   .0020 btc   6/17   .0021 btc
6/18   .0020 btc   6/19   .0020 btc   6/20   .0020 btc   6/21   .0020 btc
6/22   .0018 btc   6/23   .0021 btc   6/24   .0019 btc   6/25   .0021 btc
6/26   .0021 btc   6/27   .0021 btc   6/28   .0022 btc   6/29   .0021 btc
6/30   .0020 btc   7/1   .0019 btc   7/2   .0019 btc   7/3   .0018 btc
7/4   .0017 btc   7/5   .0011 btc   7/6   .0013 btc   7/7   .0011 btc
7/8   .0009 btc   7/9   .0009 btc   7/10   .0008 btc   7/11   .0008 btc
7/12   .0010 btc   7/13   .0009 btc   7/14   .0008 btc

Now it’s July 14, 2014.  Your original investment of 1000 kh/s is now worth 0.28 btc.  The rewards you have received are 0.34 btc.  You have paid 1.55 btc and after 3 months your investment is worth 0.62 btc.  You have lost 0.93 btc.

IF..and it’s a big ‘if’…IF the rewards stay at 0.0010 and the price stays at 0.00028 khs/btc, it’s going to take you 930 days to break even.  If the price and rewards continue to drop at the rate they’ve been dropping, you cannot make your original investment back. 
If both the price and the reward somehow reverses the trend and doubles from what it is today, your 1000 kh/s are worth 0.68 btc, putting you at a loss of 0.65 btc.  With rewards of .002 btc/day, that’s still 325 days to break even.

The rewards keep dropping.  Consistently.  The price keeps dropping.  Consistently.  There is nothing to indicate that the price or rewards will reverse their trend.