I've had a set of 3 Txi plus and receiver for 18 months with no problems at all- including the battery cover fitting perfectly.
I've used them on a 48 hour session where it rained constantly - and I mean it rained for 48 hours. Non stop. No problems.
I have even dropped one in the lake and it still works fine.
Down here we don't pay VAT so I got my set, plus the night light hangers for under £400. I don't know if that is is good value for money or not. I'll let you know in 10 years