i have tried tommy platinum and philips, and the reception of tommy is much better. at mothercare, it costs HK$1,699, but at bumps to babes, it costs HK$1,250.
I bought tommee tippee but I am quite disappointed because it doesn't work very well. The handset cannot get the signal if I put the vioice detector at bedroom and the handset at dining room. It is only 10m between them.
I also use TOMY brand premier walker (or something like that). (this is a different brand from tommy tippee) . The reception is very clear and good. I strongly recommend it. I also bought mine from bumps to babes in central (5/F, Pedder Building, Pedder Street, Central)