The H and H+ are faster versions of the 3g signal. The iPhone4 I think is capable of detecting these (HSDPA) but only shows the 3g symbol is because these 2 are basically still based on 3g technology.

Now about the internet connection speed talagang mabagal lang ang smart. I have a smartbro pocket wifi and sobrang bagal ng connection kahit naka 3g. I tried getting the sim card and used it in my note 8.0 same predicament even if the signal shows the H and H+ symbols sobrang bagal pa rin.