There are several ways to categorize these tools - and they should be considered as simply tools - so I'll categorize them by benefit...

Portability:  Do you travel frequently?  Well, hauling around a Via-jet may be a little cumbersome and explaining the device to airport security might hold you up a little...  I have two which will serve this purpose; the Pocket Care and Perioflex.  The Pocket Care and Perioflex are small - about the size of an eyedropper, so they are good for traveling or for irrigating specific deeper pockets.  They are not electronic (you have to squeeze them) but do come with the cannulae tips so you can irrigate your deepest pockets while away from home.  The Perioflex allows inter-changeability of the tips whereas the less expensive PocketCare does not, but is less expensive.  The Perioflex also has a special internal device which allows you to utilize every bit of solution in the bottle, no matter at which angle it is being used.  These irrigators are designed to 'deliver' antimicrobial solution to the effected area and saturate it - not to dislodge food debris from in between teeth, as they lack the power for that function. For whole-mouth irrigation, consider Via Jet PRO, ShowerBreeze, or QuickBreeze oral irrigators.

Faucet-style irrigators.... For convenience and ease of use, these three irrigators do the job nicely.  All three run off your indoor water supply and you control water pressure and temperature right from the shower or faucet.  Both are comparably priced, but you can get a discount when ordering both a QuickBreeze and ShowerBreeze together as a package.

For best overall performance and greatest benefit is the  new Via-jet PRO oral irrigator.  This could be compared to units such  as the WaterPik, but with more features.  The Via-jet PRO comes with  four tips - all able to do double duty above and below the gumline (4mm), rarely found with other similar irrigators.  In addition, a cannulae tip adapter is an option for the Via-jet where you need a tip that can deliver anti microbial solution into deeper periodontal pockets.  I am not aware of another similar irrigator on the market with this option.  Another feature of this unit is that I have parts for it, so if you  break something, likely you can replace the part without having  to invest in another unit.  I have valves, hose & handle kits, 'O'  rings, reservoirs and reservoir lids available...  Repairs are also available. (Please do not write and ask where the Via Jet is available in your locale.  I simply do not know, but they are normally sold through dental offices.)

"Well, Cornwell, which one(s) do you use??"

I prefer to irrigate in the shower and have the ShowerBreeze attached to my shower head.  I have a Via Jet sitting on my sink for more thorough cleansing.  I use TheraSol, Nara Powder or OraMD for brushing and either TheraSol or baking soda & salt in distilled water for irrigating with the Via-jet.  My 'significant other' prefers and uses the QuickBreeze in her sink.  I'm 52, have all of my teeth and have no problems - never had a root canal, etc. (I had fillings when I was a child).

If you want to add irrigation to your oral health routine, and you should, then hopefully I've made your decision a little easier.  Is irrigation fun?  Well, I don't know, but it is certainly healthier than not irrigating - You just can't get in between the teeth or under the gum line with brushing alone and even if you brush diligently several times a day, the safe harbor for microbes is below the gum line - where your brush & floss cannot reach.

As you get older, that's what you will certainly want to concern yourself with...

         ...Not root canals and dentures!

After you start irrigating you'll want to introduce irrigation to your children ...and their children.

Tom Cornwell
Mizar5.com

Final Note:  Before you rush out to pick up a discount store irrigator to save a little money over the ViaJet,  keep this in mind - we sell the ViaJet  for at least 2 good reasons;  If you irrigate like you are serious about it, you will not be replacing this unit every three months and... the ViaJet is the only unit I am aware of which will accommodate a cannula tip.  I do not have tips for any other units of this type out there.

(See details and descriptions at http://mizar5.com/products.htm)