Why only restrict to these two? TRE is okay as well.
I am only avoiding TT and TRS. Both are crap.
If you wonder why the opposition can't stay together, take a look at the blogosphere.
The Online Citizen split into itself, New Nation, NAR and Publichouse. 1 became 4.
Temasek Review split into TRE, Temasek Times and The Real Singapore. 1 became 3.
Conclusion: Those with big opinions tend to have big ambitions.
Those with big pockets stay together (like PAP).