What will I lose in system integration by going to an Galaxy S III?

As an actual iPhone user before I switched to the Galaxy S3 I have to disagree with the previous posts. I cannot wait for my iPhone 5 to arrive (theres a 4-6 week wait right now) so I can sell my Galaxy S3. For people that have always had Androids I can understand why they say the Samsung is better, because on paper, technically it is, by a long shot. In reality this isn't necessarily true. 

To give you an idea of what I use my S3 for so you can apply this or not to yourself, I use it to sync 3 Gmails, 1 Outlook, Surf the internet lots, have lots of apps (sports, news, shopping, I dont play games, I use the camera for basic Facebook posts and quick snaps, I also use it heavily for Music and Video. I use Maps for GPS, send text and make lots of calls.

I'll list the issues you will find, followed by what is good.

Firstly, you wont enjoy the move from iOS to Android, every thing is there, but its not nearly as simply laid out. It will seem cluttered to you. Google are awful with updates to, by the time the official Jelly Bean version is out for Samsung's flagship model, a new version will be out already, you wont get this for another 6 months. Yes you can customize the hell out of it, but why would you want to when it just bogs down the battery (live wallpaper etc)

The Samsung Galaxy S3 is not compatible in ANY WAY with a Mac Running Mountain lion or above. It simply wont connect through USB or Wifi, there are known issues with it since some updates and still not fix. Only way to transfer is by removing the micro SD card. Believe me, Ive tried, very frustrating. 

The battery life, compared to an iPhone, is NOT good, Need to charge mine mid day otherwise by the time 5pm comes its long dead. It also takes 1.5-2 hours to charge, iPhone is done in 30 minutes. Android users I spoke to said to maximise battery life you should switch off Wifi, GPS, Mobile Data and lower the brightness when not using these. this is a Pain, iPhone you dont need to do this, leave them on and the battery is still fine.

Apps in the play store are not nearly as polished as their iOS counterparts.

Device feels very cheap compared to an iPhone, this is a $700 phone and the back is a flimsy piece of plastic

Music play is poorly laid out and nothing compared to iPhone's player.

Having said all this, you may like these features

Huge screen (not iPhone quality, can see pixels when you look close) but still very nice

LED notification light for texts etc

Very light

Quick for the most part.

MX player is nice with drag and drop video files

Hope this helps. I may seem bias, but in all honesty this is all the truth. I wanted to love the GS3 but it just doesn't compare

Firstly, I'll admit I haven't had an iphone, I've been android since my first smart phone, I did have a ipod touch if that counts for anything.  As for integration with your mac I think you are kinda missing the point with android.  I have probably connected my phone to my computer twice, it's just something you don't need to do.  If you use gmail then everything is fairly automatic, you punch in your email address and password and your phone syncs everything google related: gmail, youtube, google docs, you name it.  If you use another email provider you go to the email app, put in your info and boom, done. As for contacts I imagine that is pretty much a standard no matter what phone you have.  I can't speak for battery life but my SIII goes all day, last night I plugged it in at 11 with 35% battery.  At the end of the day I can't say enough good things about this phone, it is without a doubt the best phone I have ever owned.

Pulled the trigger on an iPhone 5. I heard reception was spotty on the S3, which, I suppose I'm used to on the 4s, but I'm hoping it's better on the 5 (the same wouldn't be a deal breaker. I also like the smaller size.  

Google's ecosystem is just as good as Apple's, if not even better. Full Google apps integrationincluding: Google Calendar, contacts, Drive, YouTube, Google Plus, etc. Apps are synced across your Android devices, updates come OTA. Plus, it's much easier to move music, pics, videos, files from and to Android devices than through iTunes. Adding to all that is the fact that the S3 is actually smarter than the iPhone in almost every way. Good luck with your choice. 

I'm not a fan of Galaxy SIII per sé, but you should watch this series; it's fun

playlist at www.youtube.com

The series is about comparing the two and debunking some myths about Android and iOS. This guy will come across as an Android fanboy, and he is an Android supporter but decent reviewer, since he openly admits to the iPad superiority for instance. BUT if you listen to what he reviews - his points are valid regardless of what he prefers to use as a phone.

I, for instance couldn't believe some of the things in there.

IMHO, there are various reasons to go for Android.

It's better than Iphone 5 in almost EVERYTHING!

It's smarter than the iphone 5 in every single way