I want to answer this question, we need to know the details of both glass and plastic materials:
1. Glass: fragile, Non-aging, higher light transmittance, cheaper.
2.Plastic: tough, good PC will not turn yellow, high light transmittance, good heat-dissipation, if the PC material is not fire retardant will cause poisonous gas so please choose good PC.
So I prefer PC or PC+aluminum, most of the manufacturers produce PC/PC+AL also.
It is personal home use, PC is enough. People would say the glass is higher light transmittance. I would say you can choose 20W PC cover to replace 18W glass cover. You can see lumen to make a decision.
With today`s technology and Chips efficiency, both tubes will give you almost the same Lumens per Watt, performance. So if we talk about specs you will not find a big difference.
The big deal is about transportation, some people are concerned about broken glass tubes when they are shipped. The glass tubes are way less expensive than the plastic tubes but if they get broken when shipped it could be more expensive at the end.
However, LED Lighting manufacturers have found a way to ship these glass tubes safely. They used to do it with the fluorescent tubes before and now they do it with the LED Glass tubes, so it`s not a big deal.
So the most important is the lifespan, after long-time test and sure you can easy to know that aluminum will transfer heat better than glass, then the led light decay of glass led tube will faster than plastic+Alu led tube.