I too have been finding my GT-9505 (UK) very good with regards to GPS, both indoors and out.
On my S2, I would be lucky (and I mean LUCKY) to get a solid fix on between 6 and 9 satellites. Indoors, I would hardly ever get a fix at all.
On the S4, I regularly get a good fix on anything up to 20+ satellites in 5-10 seconds.
One addition to ironass' great post here however, is instead of fasterfix, I use Faster GPS
. This, like fasterfix, allows you to specify your NTP server, but it also gives you the ability to edit your gps.conf in any way you see fit (easier than manual edits).
For example, in advanced settings, there is an ENABLE_WIPER option, that is defaulted to 0. Set this to 1 to enable wifi positioning
Also, set DEFAULT_AGPS_ENABLE=TRUE (not set by default)
both can help speeding up your fix even further.