The most versatile weapon in the game is the Lancer. Giant clip, accuracy, can spray, and you get the chainsaw at close quarters. Active up bullets and you can take out 3+ guys rushing you with few issues. Hence why it is the weapon in the game right now that has the most kills in everything.
The Gnasher here in Gears 3 is the smoothest and best version of it in all 3 of the Gears games. It's consistent, has powerful counters, and requires skill to beast with game in and game out.
Taking two clean hits to your chest/body with an active Gnasher SHOULD down you in that 10 foot range. If you are that ill equipped/scared of a Gnasher user, then just switch to Retro. It's the most consistent counter in that range to drop Gnasher users who don't properly utilize wall sliding and evasive techniques to close the gap in order to get a precise shot to 1 shot you.
The Gnasher does not choke out areas of the map like the SOS does. If I see a SOS user around the corner I cannot approach him head on or at an angle through that path. If it's a Gnasher user, then I can engage in a well timed and angled slide to make him whiff a shot to then engage in a shotgun fight. If I try this against a SOS user their range and arc will 1 shot me 9/10 times, making pushing someone in a 1v1 situation completely impossible unless I want to be a SOS user myself and at BEST trade with him so we both die.
Gnashers the closer you are should be coming out on top IF the player is better. Are you finding shittier players are the cause of your deaths with it? Also, bitching about the weapon that is the solid base to why this games MP is fun and had it's big following is something I can't see eye to eye with, because it leads me to think you are new to being a Gears of War's online experience. Simply put, if the Gnasher is causing you woes, then this game is probably not for you.