I think they are good and very useable . I can only compare them to other digital MFX boxes as I only had one boss pedal to compare it to.
However, if you are only using it for the purpose of delay and reverb, you may want to look at at a zoom CDR which is much less expensive and the size of one stomp.
Currently I have both, but I am using my boss gt100 two ways, either putting my mustang three in the loop of the gt100 for the amp and cab models, or using the GT100 as a complete stand alone unit.
I have not used my zoom in a long time, but that's only because of the above scenario(s)