I just saw this so sorry for the delay. I know this probably doesn't make things easier, but we have to define the term "effective" and what that means to you. If we are talking about "relief", the Carisoprodol is way more likely to leave you in a more relaxed, relieved state owning to its tranquilizing properties. Meprobamate was an extremely popular drug in its day. I would say less than 2% of people I talk to about this drug were informed or otherwise were aware of the fact that its basically just a strong sedative like a Barbiturate.
As for the remaining two that we have been discussing today, that is going to really vary from person to person. You've gotta give it the old college try and evaluate the results.
There are plenty of other drugs that relax the muscles as a side-effect, but off the top of my head, these are the only three drugs that I'm actually familiar with.