I also have a very similar problem with the poor picture and would like some advice from Simon at Now Tv. As this is my first month trialling it I would like to resolve this before I commit to using it regularly.
I have had this problem recently despite having adequate broadband speeds - I have (hopefully) solved it by buying a netgear wifi extender, plugging it in next to the TV and running an ethernet cable directly into the TV from it - and have had a smooth, sharp picture ever since.
I use the NOWtv app on an LG set.
No idea whether that's a permanent solution or I'm just lucky - but for people struggling it's worth a go.
If it IS a solution then NOW should be sending everyone a voucher to buy one if it's necessary to run their service properly.
This is no solution.
I have wired connection direct to my TV and constant 40MB.
Netflix and Amazon both stream in 4k without issue. But Now TV can barely go 10 minutes without dropping to an image quality where you cant tell if you are looking at a human face or or a garden shed.
Now TV service is just plain abysmal, how you can charge people mo ey for it is beyond me!!