Animal studies show that papa bears drink too much caffeine, mama bears too little, but baby bears' intake is just right... :)

Caffeine, like any other drug, has differing effects/side effects.  In order to reach a balance, the old adage everything in moderation rears its wise head.  However, for diabetics, the germaine effect is that caffeine raises blood sugar.  So it would be a stretch to say that it's good for diabetics.  And since some caffeinated beverages have healthy effects (black coffee and green tea are high in antioxidants), it's hard to say it's bad.  The best descriptor may be necessary, as caffeine junkies across the planet would be useless in the AM without it :)

My advice- make sure the caffeine isn't unduly raising your blood sugar- if so, it may be better to cut back.  I would check your sugar 2 hours after you drink the most caffeine- so 2 hours after breakfast.  If you can't get below 180, sanka is calling... Another method would be to trend your HgBA1C- if you are trending down, all is well- if not, cutting back on the liquid speed may help.

And remember, chronic caffeine consumption may cause rapid hearbeat, or bone loss (pain), so any of these, you should cut back as well.  Personally, I would probably never give up a good cup of black coffee, so I suspect there's a healthy amount of joe for all.

Best of luck- Cheers (no, I meant that with a wine glass, not a mug)