Why would you stick with the same manufacturer? There are no prizes for loyalty.
Just go with whatever does what you want.
I had a lot of Sony Ericssons for the simple reason they did what a wanted, how I wanted. I got bored so I got a Nokia, loved it, got a Sony Ericsson again but didn't like it at all really becasue it used the same OS of the Nokia (Symbian....eeewww) which I was bored of so I went Android.
Samsung Galaxy S (it also rendered my ipod touch useless so I sold it).
I started with a Nokia, a 3310, it wasn't possible to break it.
Then I bought a brand new sony ericsson, a k650i.
This one was broken in 1-2 years, it seemed like a battery failure, since it would turn off rather fast, I bought a replacement battery but it didn't help.
So, I was bought a k700i off of a friend, which lasted a year.
Then I was given a k750i which lasted 2 years.
After that one just stopped working without warning, I looked around for a subscription-thingy.
I now pay 17 euros a month for 2 years, for a HTC Desire with unlimited internet.
Now that was a pretty neat deal!
I like the fact that android seems to grow really fast.
i will never buy a Sony Ericsson again, around 3 years ago my family all got new flip phones and they were all Sony Ericsson, one by one the screen died on all of them after less than a month of using them.