PETG - Polyethylene terephthalate glycol - is a filament with a higher glass transition temperature than PLA or PLA+ (\~80C vs \~60C). Thus, it can withstand hotter temperatures.
PETG is actually stronger than PLA in terms of tensile strength. PETG is also more durable, impact resistant & flexible than PLA or PLA+, although the lines of distinction blur with PETG vs PLA+.
PETG also prints at a higher temperature than PLA or PLA+. PLA and PLA+ print at 200-220C, vs 220-235 for PETG. Print bed temperature should be about 60C for PLA, and about 80C for PETG.
The biggest complaint about PETG is that the bed must be very perfectly level, and the print head at just the right height on the first layer. If not, you will see filament trailing behind the printhead. Once you get your printer “dialed in”, you will like what you see and produce.
Prices for PETG are very similar to PLA and PLA+.