As far as transferring between Reserve and Guard (and into Active Duty from Reserve/Guard, for that matter), you need to ask that specific question to the unit to which you will be assigned.
In RegAF, the Air Force funds all your training, food
, etc. In AFRes/ANG, the individual unit has a training budget that funds your training, food
, billeting, etc. That budget is limited, and many commanders may not want to spend their money so another unit can gain the benefit.
Also, the bottom line here is a unit recruits people because they need to have a certain staffing level to be mission capable. Regardless of whether or not the gaining unit reimburses the unit that paid for your training, the unit that paid for your training expects to have a usable airman on a certain date and for a certain amount of time.
For example, let's say you start training on 1 Jan 07, and your initial training takes 24 months. On 1 Jan 09, your commander expects you to be mission capable, and he expects you to be available to him for missions until 1 Jan 13 (6 year enlistment, right?). Anything that prevents him from getting those four years of mission capability out of his investment in your training is going to cause him to speak to you in a disparaging manner, if you get my drift.