Combined thermostatic bath shower mixer, any good ?

[wanleg]

Hi,

I currently have a Mira 415 EV which was used in my old (now mostly removed) shower area. I am thinking of installing a shower bath and was looking at a combined thermostatic bath shower mixer as oppose to separate tap(s) and shower....something like one of these....

http://www.devatap.com/deeva_detail_prod_show.asp

or

http://www.mirashowers.co.uk/onlinecatalog/shower_features.jsp?item=377316&prod_num=Excel+Thermostatic&cat=Thermostatic+Showers&from=flex

Does anyone have any good or bad experiences of these combined units ?

Also a plumber friend of mine had some concerns of using a thermostatic unit with a combi, anyone else have a take on this ?