Yes, I thought there were similarities too, and perhaps they did share ideas (the cabbie was working for Moriarty, wasn't he?  But his methods were his own).

I have to say I was disappointed with the cabbie.  I was so eager to find out how he did it, what it was that he said that would make them long for death.  Then it turned out that all he did was threaten them with a (fake) gun.  (And also funny that Sherlock doesn't "win" by any wit or skill, but by somebody else shooting the guy!). 

But I suppose it flagged up for Sherlock that Moriarty couldn't be attempting to talk him into suicide.  He had to have a threat ... and the court case had shown that it was going to involve threatening people close to him. 

It's a shame that these criminal masterminds turn out to be rather crude, and not so clever after all! 

I think Moriarty would have been disappointed if Sherlock killed himself with the pill.  Maybe it was a test - was he a worthy opponent? 

I have wondered about whether he would take it.   I agree that he has a need to prove he's clever (and a need to avoid boredom), but ... taking the pill would just be doing what everybody else did (even though they got the choice wrong).  He's being manipulated into it and knows he's being manipulated - does he want to be so easily manipulated?  There's a fair chance the cabbie is lying (both pills are deadly and he never actually swallows one.  Or he takes an antidote immediately after, etc.).   Or that the other times were just chance.  It's such a mundane thing, swallowing a pill? 

But I do think it's implied that he might have taken it ... he's not in any danger in any other way at that point, so doesn't need John to save him ... unless he really was going to take it.

I hope he wasn't, though.  It seems such a silly, pointless risk to take.  I like to think he was planning something else.

True!  But ... of course getting into the car with the cabbie was a risk, but one that of course Sherlock would take.  It was completely intriguing, as well as being possibly the only chance to find out what was happening. 

By the time it comes to taking the pill, the mystery has gone, he knows what happened, and it's not nearly as clever or interesting as he'd hoped.   He knows he's being manipulated into taking the pill. Would the lure of playing somebody else's game and winning be enough to over-ride that?   It's interesting, though, if Sherlock is the one person the cabbie actually can talk into taking the pill (instead of threatening to shoot them, as he had to do with the others).   It's definitely a weakness.

I wish we'd known the cabbie's "method" and whether Sherlock deduced it correctly.  Because the obvious way to not give clues as to which pill is which is for the cabbie himself not to know.   The only clever thing the cabbie needs to do is to convince Sherlock that he does know.   It's suggested that as the cabbie is dying anyway, he's willing to risk death, and from what we see in the scene with Sherlock, he doesn't have a way of forcing his victims to choose a particular bottle even if he knows which is which.  So it's chance.

Of course, as the cabbie says it's not chance, but it's clear he can't make the victims choose a particular bottle, the even more obvious solution is that the cabbie is lying.  Maybe all the pills are poisoned and he never takes his (how would anyone know?).  Maybe he's immune to whatever poison it is. 

Either way, it doesn't make any sense for Sherlock to take the pill.   It's not a game.  It's either a 50/50 chance, or a certainty of death. 

(Unless he knows something we don't, in which case I like to be told .  I love hearing how he does his deductions).