Opinion are like elbows everybody's got a couple, right?
Revolvers vs. Automatic
Want to survive a gun battle you need
Simplicity, Reliability
A lot people think of revolvers as "simpler" and, therefore more reliable. In reality, the average revolver has more parts than the average automatic -- some twice as many. Just look at an exploded parts diagram book and count a few. You might see 40 or so for an automatic, 50-80 for a revolver. Revolvers look simpler, but they really just have all those parts hidden away.
A revolver must hold each chamber in the cylinder perfectly aligned with the barrel, perfectly spaced from the barrel. It also must have perfect "timing", perfect coordination of the cylinder moving, the hammer dropping. The cylinder not aligned or the hammer drops too soon, the bullet shaves lead.
The alignment and timing are so critical that it makes many parts of the revolver very critical in dimensions and alignment. Take a box of parts for a Colt .45, assemble them with a few tools, and you'll have a working gun. Take a box of parts for a S&W revolver and assemble them and you won't -- you will need to do adjustments, alignments, bend and file to get the timing right. The book on pistolsmithing called Pistolsmithing by George Nonte has much more information on revolvers than autos, the author a big revolver fan. But look what he states in these two chapters:
19) Rebuilding an Autoloader: "With most autos -- at least those that are worthwhile -- rebuilding is simply a matter of replacing parts. The typical big bore auto ... is designed for complete replacement of all parts with minimum tools. ... I might add this is the method used to overhaul military sidearms and restore them to full serviceability."
20) Rebuilding a Revolver: "The last chapter dealt with rebuilding autoloading pistols which are generally quite easy to work with. Revolvers are a bit more complex and simple part replacement often won't get the job done."
. Reliability means being able to work right, and to always be able to.
The one thing that can make or break some autos is the Ammo used. Just about every auto has no trouble with FMJ ammo. Hollow points bother some, as do shorter rounds. Top of the line autos like some I will mention at the end can take any ammo you give them. Revolvers are quite tolerant of ammo except for one thing -- don't let it hang out the front of the cylinder!
Your Bang for the Buck.......
A cheap revolver that is fairly new and working properly is far more likely to work when called upon than a cheap automatic. Avoid cheap autos at all costs. Avoid anything but the tip-top quality auto if you need one that fires a rim-fire or rimmed cartridge.
Usage Differences
Reliability issues aside for the moment, what are the actual differences in their use?
An automatic can hold a lot more rounds than a revolver, and is easier to carry extra ammo for and to reload it. It has less recoil than a revolver. It can have a longer barrel for the same gun length. An auto is also flatter and easier to conceal. An automatic can offer lots of types and levels of safety systems -- none (like a revolver), up to squeeze cockers like the H&K P7. (Safeties are a whole different subject)
A revolver takes much less training, just aim and pull the trigger. No safety system, either. Always keep a revolver holstered, that is the "safety" for the gun. Don't reach into a desk drawer, or under a seat for an unholstered revolver, you may get a bad surprise if you grab the trigger by accident. No training on clearing a jam is needed (as is with an auto), just pull the trigger again. Revolvers tended to offer higher power levels, specifically the .357 Magnum vs. the 9 mm. The .40 S&W auto is catching on, and it closes the power gap -- at the cost of less rounds in the gun.
Bottom Line
It used to be rare to see a cop with an automatic -- these days it's rare to see one with a revolver. Departments convert over all the time for many of the benefits I've listed above. And you won't see a soldier with a revolver too often either.
My bottom line advice to you is to buy the finest double-action automatic you can afford. Buy one with a 3 safety system -- a lock on the firing pin released by the trigger movement and a manual safety that locks the firing pin and blocks it from the hammer (or H&K's squeeze cocker). Leave the manual safety off when it is in a real holster attached to you. Insist on a loaded chamber indicator. Don't buy anything smaller than a 9 mm unless you want to piss someone off instead of stop them. Get a 10 mm (not .40 SW) with full load ammo if you have serious needs, say a S&W 1006. Look at guns from H&K, Beretta, SIG, S&W & Glock. You don't have to be

just think out your needs and buy accordingly.