Perry is new to the scene. Thus more attention towards him. You are right though, most know what Romney is all about. So why bother pointing out the obvious. :-)
I don't know for instance if a single Mass. cop ever detained a single illegal alien under Romney's watch, while Perry has ordered Texas rangers to the border than detain hundreds each day. Perry went along with 99% of the Texas legislature and signed a bill allowing the children of illegal aliens who have lived in Texas for the previous 3 years to receive in-state tuition rates (which they would have easily passed over his veto) while Romney is the architect of Romneycare the precursor to to Obamacare, and 70% of those using Romnycare are illegal aliens. Romney also as governor issued an executive order to all state agencies to implement gay marriage. I could go on and on.
Anything that Perry is bad on, Romney is 100000 times worse on. Remember that even McLame seemed conservative by comparison to Romney. I remember this, and maybe you remember this, but obvioiusly many here don't since many appear to be considering Romney instead of fighting like heck to sink him!