I don't know. At 1500 I've been fantastically disappointed in Praetorians.
At first I thought 'Great! Finally an answer to the deathstar.'
But they're so expensive, and initiative 2 is a killer. This is what makes Wraiths work. They're the only unit in the entire codex (aside from a C'tan I4) that has a chance of going first. That sucks. It's a huge hole to be in. It would be different if they were all carrying the equivalent of fists.
On the Fearless thing: In both my games I took so many wounds, that even though I didn't run, the 'extra wounds' caused the rest of the squad to die anyway. At one attack each (two rushing in) it's just not enough to offset the cost.
The Covenent Rod, or so I thought, would be their saving grace. But it wasn't... the problem is it IS great for shooting Terminator style Deathstars, but you often lose assault range as a result.
The Particle caster and Void Blade seems ok, but rending blows. The Entropic strike in CC is best for vehicles.... I don't like the idea of a non-power weapon, non-invulnerable save squad going against an uber character and hoping to get an Entropic Wound on him/it/her.
I am so frustrated with Praetorians, I am willing to rip the Covenent arms off and try something else. I don't know what, but at 200 points for 5, it's REALLY hard to make them work better than say.... Flayed Ones or Scarabs.
The thought of using them against vehicles is a neat idea, until you realize that scarabs do it better, faster, and cheaper.
But I haven't honestly tried Praetorians with Particle Casters and Void Blades. I'd love to hear from those that have. My big question would be, can 5 of them stand up to a deathstar? If not, I won't take them. I have enough mediocre close combat junk in my army as it is.