I don't fly either, however I do have a current copy of Business & Commercial Aviation in front of me and I'll share the differences as displayed in their Purchase Planning Supplement.
For starters the ERJ 135LR cost $18,000,000 and the Corporate version is the EMB-135BJ or Legacy 600 cost $25,408,000. They both have the same external dimensions and the first difference I come across is the engines. Believe it or not the Legacy has the same engine but more thrust by about 500# per side. The Legacy also has a higher Max ramp weight;
49,758 vs 44,312. The airline stats use different verbage than the corporate aircraft so bear with me. It looks as though the legacy has a celing of 410 vs 370 for the EMJ 135. Mmo is also slightly higher for the Legacy at .80 vs .78. The fuel is the big difference with the Legacy having 18,170# vs 11,327#.
That's about all I can muster, hope that helps....