I have nothing against flat packs in the right environment. not something you want to use in an RF dense site but as a stand alone in the middle of nowhere your probably good. in our world at such low power a flat pack will be fine at 1.2-1.5 db insertion loss and 75dB isolation between the ports for $$ as oppose to a .5dB insertion loss and 100+dB of isolation for a TX-RX $$$$$ in the real world a 40W input will give you 28-32W out if tuned properly. now the $$$$$ unit will give you 36W. it all depends on your budget, location and expectations of the system. as to RX sensitivity that I find radio dependent, some are good some out right suck. I personally like Kenwood as their receivers will typically do .25-.27uV out of the box. I have seen them go as low as .18-20uV after a tune. just my thoughts.