I highly recommend airsoft as a training vehicle.  Not necessarily the running around shooting other guys but to maintain skills with the manual of arms.  The gunfights you and I likely to be involved in are more about gun handling than tactics.  Can you get good center of mass shots from your holstered pistol in the time necessary to not place 2d in the fight?  Professional training will provide the initial skills but they're perishable.

Dick's (AKA Toys-R-Us) airsoft or the $19 manual cocking gun show guns are of little use.  Like most things quality items provide the most value.  A good airsoft gas blow back (GBB) pistol runs about $150.  Good GBB M4 carbine will be close to $400.  You'll need green gas and BBs.

The value of airsoft is how easy and often I can practice (recall that practice without training just reinforce bad or inefficient skills).  My 1/2 acre suburban lot has more than enough range to shoot airsoft safely.  I can hang a blanket backstop in my garage or basement during the winter. In fact I've sold my .22LR AR15 since even that requires a trip to the range which is at least 45 minutes away.  

At pistol ranges, say 10 meters and closer, either of my gas powered pistols will consistently put BBs in the 0-ring of a standard IDPA target if I do my job during the presentation from the holster. As gas guns there's the ability for follow up shots and the recoil (while mild) is enough to disturb the front sights during followup.  Trigger press, reset, press.  I can knock down 9" metal silhouettes easily at the same ranges.  Limited magazine capacity requires mag changes when the slide locks open.  

Rifles are similar and at longer ranges.  Good airsoft carbines mimic their cartridge versions very closely.  Same manual of arms, same sight pictures, etc.  The manual of arms is critical.  No airsoft gun offers the same stoppage clearing training of cartridge gun though.

I've been using KWA Professional Training airsoft for about three years now.  M4 carbine, M9 and M1911 pistols.  These are all gas powered with very satisfactory simulation of my service weapons.  Green gas is relatively expensive but BBs cost less than a penny.  To minimize the "tracer effect" and force myself to use the sights a I use dark colored BBs, not white.  Biodegradable BBs will just blend into your lawn.

Automatic Electric Guns (rifles) use a rechargeable battery and magazine capacities over 300!  Not real training for me.  KWA makes an RM4 "electric recoil" M4 carbine with simulated recoil and a switchable magazine capacity of 30 or 60 rounds.  Very nice gun and recommended.  And you can also use one of those 300 round magazines if you want.

And after a long day at work it's sometimes time to just put the selector of the LM4 (or RM4) on CROWD and sent a full magazine down range!  

-- Chuck

If you have a real range you're in better shape than many of us.  I have a 30+ minute drive to even shoot .22LR which is really no better than airsoft albeit with some more range.  Hold-over etc is not a great match past 50 feet.

To be effective (IMO) ya need premium aifsoft guns.  A good KWA LM4 or RM4 costs about 60% of a base AR15 and gas for the LM4 adds up the cost.  The "cartridges" though don't even count as an expense.  2000+ of quality biodegradable BBs runs maybe $20.  Don't need earplugs or exotic eye protection either.

As noted I can shot drills daily off my patio or in my garage (where a large pad of scrap carpet protects the wall) daily.  Even in my pajamas.  

-- Chuck