On balance, for me, it's very much better. Bell's 'not out' only goes to show that it's still not perfect. Using Hot-spot as the sole decision maker is flawed. Using a combination of information from Hot-spot, Snicko, the stump-mike, and the umpire's original opinion would have lead to the correct decision. None of the tools available on their own are perfect. And I'll also concede that even with a combination of all of the tools available, I still don't believe it's perfect. Technology will get better and quicker though.
Apparently, Snicko is not in use in this series because it takes too long. That seems silly. In Melbourne Kevin Pietersen was correctly given not out in similar circumstances. But it was only later when Snicko showed that there was no sound as the ball passed the bat, that people felt much more confident that Pietersen was in fact not out.
Does the use of technology and players and umpires being able to refer for advice make for a more correct decisions? I would say definitely yes. Johnson and Beer have both had wickets reversed because the umpires can now check for a no-ball. Does that minimise the impact of the incorrect decision influencing the outcome of the game? Yes it does. In recent years there have been many examples of decisions going against batsmen when they clearly edged the ball into their pads, and decisions going against batsmen for bat-pad catches when they've made no contact with the bat. Damien Martyn and Stuart Clark getting very bad decisions in the same innings in the 2005 Ashes.
Two things though. Use all the technology available - Bell should have been out, and would have been given out if the 3rd Umpire was allowed extra time to review that. Though I'm not sure why Hot-spot seems to have over-ridden the evidence of the stump-mike, and Aleem Dar.
And secondly the tactical use of the team's reviews needs to be addressed. Atherton made a good point that Bell may not have reviewed the decision if he'd been batting at No 3. Batting at No 6 with 2 reviews left, he chanced his arm, and got away with it. But the flaw is not with the batsman. They get rough decisions, and don't get a 2nd chance. I'm of the view that they should wait for the umpire's decision. Bell's decision was flawed because they didn't use sound. Batsman all know when they've hit the ball. Even feather edges are felt, and when the bat is so far away from everything else, the excuse of "my bat may have hit my pad on the way through" can't be used. Bell just gambled on a small knick not showing up on hot-spot.
For me, the value of the increased use of technology is that there are less bad decisions, so there is less impact on the result of bad decisions, which means that increasingly the best team will prevail, and spectators are not left wondering what might have been if bad decisions had not directly affected the result.