1080i or 720P?

[jaffa]

Im sure this question has been asked before but i couldnt find a good enough answer in the search i did.I have a PIONEER 436SXE (UK MODEL)that does 1080p but i can only get my PANASONIC BD10A (NORTH AMERICAN MODEL) to output 1080i.The 1080p is greyed out.Would i be better having it output 720p instead of 1080i

Also my tv says that it is 1125i when i input 1080i from the player and 750p when i output 720p from the player

Thanks for any help

Jaffa