The requirements vary widely for reserves officers and deputies, based on my cursory research. I can speak from personal experience though, too.
At one extreme, some agencies, like LAPD and LA Co. Sheriffs, require reserves to take an academy that is close if not identical to the regular academy...over 600 hours. At the end, you are POST certified, and sometimes can even work alone or with another reserve on patrol. From LAPD's website:http://www.lapdonline.org/get_involv...basic_view/542
Level I and II LAPD Reserves: Level I and II Reserve Officers perform the same functions as regular, full-time police officers. They are armed, uniformed peace officers who work in police vehicles along with full-time police officers.
Many smaller and rural agencies do not have their own academies or don't send their reserves through a state academy for budgetary reasons. My agency, the 2nd largest SO in the state, runs their own reserve academy which is about 250 hours, iirc. You then work on patrol with another f/t deputy, and if you put in another 100-150 hours training with an FTO (after a few year in service), you can become driver authorized and work alone (I haven't...I like working with a f/t partner). The PD in my city has essentially abandoned their reserve program (the previous chief did it), which i thought a mistake.
Some small agencies have minimally-trained reserves, a liability imho. In MT, a f/t hire can work on the street in uniform (after an FTO period) for up to a year, iirc, before they have to attend and graduate from the State academy. LE agencies in MT are often the poor, redheaded stepchildren, budget-wise at least.
So, investigate your local agencies. Some treat reserves like f/t cops, appreciating the extra manpower...in small MT counties, they may have more reserves than f/t cops. Some agencies (and some individual officers) don't treat them nearly as well. In some states, as a reserve you do not have f/t peace officer status 24/7 (if you are not POST certified or if the agency doesn't authorize it). That doesn't bother me that I don't...I have no intention of being a cop when off-duty...just a good witness and citizen who has more LE training than the average bear.
BTW, I have a CCW permit (nice to live in a shall-issue state), so I can carry personally and don't need the badge for that. In CA, being a reserve can be an advantage because as sworn LE you CAN carry CCW, in a state where it's can be hard to impossible for a non-LEO to get a carry permit in most counties and cities. That can be worth it, a bonus on top of the good reserve experience. Carrying CCW isn't enough reason in itself to become a reserve, imo, because of the time commitment to become and be a reserve.
It has been a rewarding experience for me. Check it out. And as someone here said, some agencies also have a Posse and/or Search and Rescue teams with volunteers, which are often unarmed, non-patrol positions but can also be fun and good.