I just thought it would be a shame to waste the time you have put into the Corps. This would also keep your rank and MOS up to date and perhaps even get a promotion or two. I was never sorry that I did the same thing when I decided to get out of the regular Army after 6.5 years. Of course I did go into the Air Force Reserve in '53 and stayed in it until 1961 when I switched back to the Army to get back on jump status with the Army Special Forces Reserve.
So I would up having 30 + years in the Army, AF Reserve/NG and the Army reserve SF, as well as 34 years in local LE. During my time in local LE I served as a Rescue Recovery SCUBA diver, Motorcycle Sgt. Bomb Technician, Riot unit Sgt., SWAT team member and Supervisor of the Traffic unit, Bomb Disposal Unit, SWAT unit and VIP Protection unit. Most of such assignments came to me because of my military background and specialities. As a supervisor of these speciality units I always look very carefully at a candidates military background and military specialities. (Of course, I did my time in Patrol, as a Patrol Officer, Patrol SGT and Patrol Lt. too.)
The biggest problem I see right now for anyone seeking a job in Federal or Local LE is that very few are hiring at the moment. The other factor is cut backs on currant retirement and medical benefits to LE retirement plans. Some have LE agencies (To include my old department,) have already cut out the retirement plan I retired under. Those that retired under the older plan are fine. The reason I mention Retirement plans is you should really look very carefully at whatever agencies retirement and benefits package before joint that agency. Many have not changed their plans yet; however, will in the future, perhaps they will 'grandfather' the people hired into the old plan. This is another great reason to do your 20 in the USMC or other Reserve/NG unit. (The Retirement/Medical Bennies.)\
There is also another danger, specially lately, many politicians are trying to remove and unionization or benevolent associations , who normal negotiate pay raises and benefit packages for LE civil servants. IMO, without such people having the power to negotiate for them they will be at the mercy of the local politicians, who will never give them a raise or good benefits, as they will be to busy taking care of pet projects, themselves and other politicians.
I know that right now thinking about retirement is difficult; however, IMO it is VERY important in todays diminishing retirement benefits and medical coverage.
Thanks its funny you say that, today is the first day that the idea even came across my mind! I just need to find someone who knows a little more about it.