Currently maining a Rogue.
Death Trap is EXTREMELY breakpoint-heavy. You MUST hit at least 3 of the breakpoints that are listed on any of the builds and there should also be a Paragon requirement of 250 for this build to work decently and not infuriate you with sitting idle, waiting for CDs to come up.
Heartseeker is a lot of fun if you're into linear pushing in pits. You will see steady improvement but if you're into the ADHD gaming of speed running, while also having a push build, it isn't for you. I do think that Heartseeker has a decent speed build, but nothing compared to the speed that you can clear T4 content {Undercity, sub 70 Pits, Infernal Tides, Dungeons} with Death Trap. To grind out your Glyphs at higher para, definitely swap to Heartseeker.
If all that you're wanting to do, is T4 content, I would go Death Trap. Mipy has a great, REALLY great build guide on Mobalytics for it. As well as a spreadsheet to tell you what to fix that you can copy and fill in with your current setup. The only thing that I can tell you in terms of Masterworking, is make sure that you get an item with a GA, to crit your masterworking on the Neck/Rings etc. It helps a ton when trying to hit the breakpoints. You can worry about specific GAs later, but even a GA Lifer Per hit or whatever, to get thatn 800 ilvl and crittable Temper on it, helps a ton.