Not only D2h, none of the dth installers do proper installation/alignment.I had dishtv in the past and now have D2h since 2010. In both cases, I myself have fine tuned the dish.
Tata Sky guys do the installation properly. No signal during rain is common thing as dish size is small but i too felt the d2h dish installation service is not good as others.
I dont know that How tata sky guys do Install dish better compare to other dth, but here in my appartment tata sky signal is affected more than any dth service
if anyone have signal problems dn go 4 cable bt ur freedom to select channel is gone nd dere signal can go in any weather i had d experience of cable tv