Glycerin is an ok ingredient. If you've recently colored your hair however, you should wait a few days before using a product containing it. Color takes a few days to set, and using glycerin during that period can cause fading. This article should be helpful.

If your hair isn't colored, then the aspect of glycerin to be aware of is that it's a humectant. That means it attracts moisture from whatever is most moist, to whatever is driest. For hair, that means that in dry weather (low dewpoints), glycerin will pull moisture from the hair and into dry air, causing frizz and dryness. In mid-range weather (average dewpoints), that means that glycerin helps maintain a good balance of moisture in the hair, without overdoing it. In warmer weather (high dewpoints), glycerin can pull too much moisture into the hair, causing it to poof and frizz and become overmoisturized.

That's the basic rule of thumb, but there are exceptions. Some people find that their hair plays well with glycerin containing products regardless of dewpoint, others sucessfully use it in high dewpoints (where the "rules" say to avoid it), but can't use it in lower dewpoints.
CG since 11/2011
2c /3a F /Mii, low porosity

Winter Products /Routine:
Clarifying: ACV rinses, Suave Professional Men Deep Clean Peppermint
Low Poo: Renpure Luxurious Argan Oil
Co-washes: VO5 Kiwi Lime Squeeze or Strawberries & Cream
RO: VO5 KLS or S&C, Cure Care
LI (if needed): VO5 S&C, VO5 KLS, Cure Care
Stylers: FSG, L'Oreal Studio Clean gel, Tresemme Flawless Curls Bouncy Curls gel
PT: IAGirl's as needed
Trying: Tresemme Expert Selection Perfectly (Un)Done Conditioner