I like pump and semi but if I had to choose Pump...Pumps are more reliable, more shell conservitive, And just a little more resistant to weather. You can get some dirt, rain in the thing and its still chambering shells. I have a semi and its pretty good but gets jammed more than a pump
By the way...
Semi- Remington 11-87
Pump- Remington 870 aka "The Work Horse" or as my cusin like to call it "The Merganser Magnmum"