The low end Trantecs are identical to the low end Sennheisers. I`ve sold quite a few of them without problems. The only drawbacks I've found is the switch is easily knocked and they use PP3 batteries which ups the running costs over units which use AA's. I've sold quite a lot to schools without any comebacks save the odd broken lav wire.
I don't think you need have any misgivings about recommending Trantecs tho the low end models don't have a mute switch.
At work I use Sennheiser G2 body packs which are pretty bomb proof (tho not 'talent proof') and will run for at least 6 hours on Procells.
Ron