This is the 12793rd most frequent Polish word.
niezłej
"Pretty good" or "decent."
The word 'niezłej' is used here as an adjective describing the quality of the equipment. It implies 'decent' or 'good' without being overly emphatic.
Mam niezłej jakości sprzęt muzyczny.
I have music equipment of decent quality.
In this sentence, 'niezłej' describes the physical appearance of the friend, suggesting attractive or appealing appearance and is treated as a casual or restrained compliment.
Spotkałem koleżankę o niezłej urodzie.
I met a friend with a decent beauty.
Here, 'niezłej' refers to the size of the bag, emphasizing a notable size but not extreme or extraordinary.