O.k - tried to resist adding my drivel but here goes.
Had a look at your links (Mekk Potenza & Poggio).
What I gleaned from them is that the Potenza has the more relaxed geometry *comfortable distance bike* & the Poggio a little more aggressive (still comfortable if it fits properly - probably).
The Mekks look good value for money for a carbon frame (given the discounts) & are very upgradeable.
The Mekks also seem to employ only a partial group set with brakes, chainset, & cassettes etc being own brand or lower spec items.
One thing to remember is that 'not all carbon frames are created equally' & there are scores of alu & carbon frames of same or 'near as makes no difference weight'.
Carbon frames are though often more comfortable than aluminium though a bad carbon frame won't be.
You could use the bike 'as is' for 18 months then swap out the whole group set for full Shimano 105 10 speed (after saving up) & have a cracking spec bike.
Alternatively
@vickster suggestion - Giant Defy 2 (ash cycles) or even the 2013 Defy 3 (ash cycles) are great bikes & upgradeable being one of the best Alu frames on the market.
Cubes Peloton 2013/14 or even Peloton Race 2013 (if you can find one) will be in range & recieved excellent reviews in Cycling Active (Mar/April) & Cycling Plus (May edition).
The Boardman suggested upfield will be a safe/good bet also.
Try before you buy is probably best bet (though I just took a gamble).

& hope you find a great bike & enjoy your cycling.