Samsung galaxy tab vs samsung galaxy tab plus (both 3g)


Im getting a which I mostly will use for reading samsung galaxy tab tomorrow . I read on the forums that the plus is weaker than the p1000 but how do both 3g vons compare to each other. I was also wondering is it worse than the samsung tab 10.1 for reading and how does the 7 and 10.1 compare to each other .
I was also wondering if the samsung galaxy tabs can make phone calls and texts?
I heard samsung wont be upgrading the original tab to 4.0 but can I unlock it and upgrade it to 4.0 myself?
Thanks for your help