Plastic can work. I've made some good batches in plastic. Glass is better in my opinion. My beef with glass is two fold. First, it requires careful handling to avoid scratching. Scratches are hard to sanitize. Two, it's not always impermiable to oxygen. Some plastic containers can allow for oxygen to stale the beer during long term storage (like high gravity beers or during lagering).
Glass carboys make great beer, and the stainless conicals are damn nice (but overpriced). If you want a top shelf fermenter, get your hands on an old stainless steel 10 gallon corny keg. They can be hard to come by, and they can get pricey (paid almost $200). This is an absolute no brainer if you already keg but still worth while if you don't. You cut your dip tube a hair short so when fermentation is complete you can transfer the beer from the fermenter to you serving containers or secondary fermenter under CO2 pressure. No oxygen contamination, no exosure to unsanitary conditions, simple and clean.
If you already keg it's even easier. You rig up a jumper to transfer from fermenter, to keg, under CO2 pressure. The beer is never exposed to air let alone other equipment. I went to this process and will never go back. On a typical batch of ale I pitch yeast and seal up the fermenter. Ferment in a thermostatically controled fridge for 7-10 days at the desired fermentation temp, then drop the temp to about 35 degrees for one week. This week at cooler temps takes the place of a secondary fermentation. The cold temps cause the beer to settle out and clear up quite nicely. Then on kegging day I sanitize one keg and one tube (the jumper) and just pump it to the serving keg. I then hook up CO2 to the serving, store at serving temp for a few days and it's ready to drink. The beer is essentially seeled in a sanitized container from the point I pitch yeast till I serve it with no exposure to unneeded equipment or air that may contaminate.
Anyway, sorry for being longwinded and not foucing on your question, just a suggestion worth considering. PM me for a source on the 10 gallon corny kegs if interested.
Adrock1