I went for the Iboost+ and it's not bad. Our meterbox is 15m away, behind 40mm of foiled PIR and a reflective VCL and there's no issue with signal. I picked it up used so it isn't on the latest software; this means it starts diverting at 200W or so. The latest ones are configurable between 100 and 500W I believe, to allow better integration with battery systems.