Don't worry about the double posting...

Using the same numbers as earlier, the S5 would expect to make 0.009541BTC a day.  Taking out power at $0.10 per kWh, the S5 net you about $1.25 a day - roughly the same as the S4.  This is where the efficiency comes into play.  Yes, the S5 has a lower hash rate, but because of the efficiency of the miner, it makes the same net as the S4.

Put it this way... Even if the S5 costs the same as the S4 (don't forget to account for a PSU), you'll continue to remain profitable with the S5 because it's earning back more per hash than the S4.  In other words, because it's more efficient, it'll weather the difficulty adjustments better than the S4 and continue to be profitable.

Glad to help.  I'm assuming the 453GH/s units are S3+.  I'm also assuming the 2TH/s unit is an S4.  The S3 requires an external PSU, so there's that cost.  The S4 requires you to purchase a power cord (a cost, albeit a minor one - unless whoever is selling it to you will provide the power cord as well).  Also, I'm not sure where you're located or what kind of power you have access to, but realize that the S3s can be spread out over multiple circuits, whereas the S4 will be on one only.  Further, the S3s will each require network cables.  The S4 would only require one.

Finally, understand that these units are tech from a few generations ago.  The S5 is a more efficient unit (~1155 GH/s for 590W) and the S7 is a more efficient unit still (4.86TH/s for 1210W).

Just for a bit more understanding of what it means to you from a profit standpoint (and this only uses current numbers - it does not make adjustments for any changes).  At the current network difficulty, exchange rate and we'll assume a power cost of $0.10 per kWh...

S3+ expects to make 0.003742BTC a day.  355W at the wall will cost you $0.85 a day to operate.  Current exchange rate means you'll make about $0.19 a day.

S4 expects to make 0.01652BTC a day.  1400W will cost you $3.36 a day to operate.  Current exchange rate means you'll make about $1.25 a day.

Glad to help.  I'm assuming the 453GH/s units are S3+.  I'm also assuming the 2TH/s unit is an S4.  The S3 requires an external PSU, so there's that cost.  The S4 requires you to purchase a power cord (a cost, albeit a minor one - unless whoever is selling it to you will provide the power cord as well).  Also, I'm not sure where you're located or what kind of power you have access to, but realize that the S3s can be spread out over multiple circuits, whereas the S4 will be on one only.  Further, the S3s will each require network cables.  The S4 would only require one.

Finally, understand that these units are tech from a few generations ago.  The S5 is a more efficient unit (~1155 GH/s for 590W) and the S7 is a more efficient unit still (4.86TH/s for 1210W).

Just for a bit more understanding of what it means to you from a profit standpoint (and this only uses current numbers - it does not make adjustments for any changes).  At the current network difficulty, exchange rate and we'll assume a power cost of $0.10 per kWh...

S3+ expects to make 0.003742BTC a day.  355W at the wall will cost you $0.85 a day to operate.  Current exchange rate means you'll make about $0.19 a day.

S4 expects to make 0.01652BTC a day.  1400W will cost you $3.36 a day to operate.  Current exchange rate means you'll make about $1.25 a day.

Really depends on your situation.  What are the upfront hardware costs?  What is the power cost?  What is the efficiency of the miners?  What are the hidden costs (i.e. you need to purchase external PSU for the smaller miners, but the larger one has PSU incorporated)?