Like anything its all a bit of a minefield,,depending on so much ie what sort of space you have on your pedal board, what do you actually need, be it effects or amp models and effects,,,the line6 M series M5,M9 and 13 have been a staple on many pro boards, Griff has an M13,,
the M5 especially is seen on many but that can only produce one effect at a time,,,switching to another can be a bit of a pain,,,i used to have an M9 but two big,,,got an M5 but i needed to string several effects together,,,,,best cheap solution? the G3nx ,,,,
The effects are just as good and easy to set up as the line6, though as i mentioned before due to the lack of outputs you cannot use the 4 cable method so if you want to use the drive pedal models it has to run into the front end of your amp thus putting modulation etc through the front as well,,
I have tried it using the amp models etc straight into the effects loop return just using the power amp and it does sound pretty good