need some opinion on switching iphone to samsung galaxy s 4g

Hello mods and all my friends, how is every one today.?  I have couple questions hope some one can help to clear it out.

i have an iphone 4 as we know it can does personal hot spot and facetime,. I had a quite hard time to get it working with Tmobile, but i did and it works for me. Now Tmobile has Galaxy s 4g with these features and cheaper than Iphone 4, so i am thinking to switch to Galaxy s 4g.

has any be able to do (facetime) video chat from galaxy to iphone 4 facetime, does it need additional app to do video chat to be able to facetime with iphone 4 from galaxy fone.  The Galaxy is video chating with 3g right, or i can also be doing video chat thru wifi, will i be surprise with the data charge??

personal hot spot Tmobile charging like $15/month for that special service, I got personal hotspot worked with my iphone 4 thru Tmobile with out paying for that service. is there any way around to get personal hotspot work with Tmobile galaxy s 4g and get around and not paying for that service.

I've been reading around quite a bit, but still not get clear out my questions, any help will be very appreciated, Thanks mods and all the friends here. have a good day every 1.

I've been an iPhone user for a long time and it works for me. BUT it is slow (3GS) so switched to Galaxy.  It has been hell so far.  Days of intensive trying to get it to work for me.  Everything about it is far different from the iPhone, so if you are used to your phone, beware.  Buy a returnable phone.

I'm really committed to making this work, but,so far, it has been a fulltime job and still!  (that's why I'm here).

This T-Mobile Galaxy S 4G is the most annoying phone I have ever owned.  Sure it CAN do amazng things WHEN and IF it wants to!  But it is S L O W, crashes too much, losses coverage (now THAT is more likely the lousy T-Mobile Service than anything else), and causes me more problems than rewards.  Meanwhile any of my friends with the iPhone (and a different service provider) LOVE and RAVE about their iPhones.  So just as soon as I can get rid of this Galaxy S 4G AND T-Mobile I am jumping ship.  My advice - Don't Do It!