Since launch date, I would say about 99% of my gaming time in Gears3 has been on Horde.
Great to see some top tips posted here, and at "The Dom Knight's" thread.
Personally, the first time I beat Wave50 was on Trenches, with 4 guys I didn't know, all 5 of us strangers to one another, all with mics & headsets. Was such a thrill! Took us about 4 hours to beat wave50 onNormal...my top tip for Trenches at this (and maybe would work with higher difficulty settings) setting, was to have all 5 guys in "the pit" / bunker in the middle of the map, with the 3 command posts surrounding it.
We bought a Silverback are wave 23, and deployed him on one side of the map / entry ramp to the pit. I held the central ramp entry point, one guy on the opposite side entry ramp to the Silverback, two guys at the back near the sandbags to avoid the horde spawning & to issue orders about where the horde was coming from.
Boss waves on this map were pretty straightforward...the only ones we really had to leave the pit for, we're the Berserkers & Corpsers. Bunkers were no problem with the Silverback, and Boss50 was a Brumak who wasn't able to enter the pit.
I'm really keen to beat Horde on Insane with a group of 5, all talking, co-ordinating & playing for the team. Add my tag, send me a message & maybe see ya on Horde for Insane!