I have had a GNX2 for the last year or 2 years or so and Im going off digitech rapidly.

Boss do make the odd really crappy stomp box (like the GP-20) however most are OK though I haven't tried there multiFX boards.

Boss have a reputation for building indestructible pedals so there is probably not too much risk going second hand !

I also think they sound nicer than Digitech.

I'd go for second hand Boss kit.