Puron or R-22? What is different about R-410A or Puron?
There are several differences. R-410A operates at much higher pressures than R-22 and requires different lubricants. R-410A also has a greater affinity for moisture absorption than R-22. These differences make special tools and training for service technicians mandatory. However, it is likely that all major manufacturers will begin producing units that operate with R-410A

R-22 Phase-Out Timeline
As a reminder, here is the projected timeline:

January 1, 2010:
65% reductions in production, using the 1989 cap as a baseline. After 2010, chemical manufacturers may still produce R-22 to service existing equipment, but not for use in new equipment. As a result, HVACR system manufacturers will only be able to use pre-existing supplies of R-22 to produce new air conditioners and heat pumps. These existing supplies would include R-22 recovered and recycled from existing equipment.

January 1, 2015:
90% reductions in production, using the 1989 cap as a baseline.

January 1, 2020:
Use of existing refrigerant, including refrigerant that has been recovered and recycled, will be allowed beyond 2020 to service existing systems, but chemical manufacturers will no longer be able to produce R-22 to service existing air conditioners and heat pumps after this date.

What is the real story about the future supplies of R-22?
R-22 is expected to be available for the next 20 years. Although the Clean Air Act  required a “cap” on R-22 new production beginning in 1996, the annual cap has never been yet been reached.  Also, since R-22 must be reclaimed and turned in for recycling when performing unit charges, the supply of R-22 is expected to be available past the life of any equipment installed during the next 10 years.