Hi KiwiSpyGirl, If you go to www.huaweidevice.com
you can compare X3 to X5 specs.
I had a look and X3 is U8150 platform but is Android 2.3 (Gingerbread).
X5 is U8800 platform and is Android 2.2 (Froyo).
X3 has Front face 3.2 mega pixel camera for Skype
X5 has 5 mega pixel camera only. It has Swype installed for keyboard and 3.8 Touch screen.
X3 has Fast Boot option.
They should both handle Google Sky but the resolution on X5 will be better.
This link will give you a large selection of Free Apps to Download:Top Free in Apps - Android Market
Hope this helps. Neil.
ps. "Words with Friends" requires Android 2.1 or higher so there shouldn't be any problem running that on either.