Ubuntu uses a Live CD which means that you can run it from the CD to see if it
is working to your satisfaction. If the Live CD boots and you can use Ubuntu
including the wireless then there is a good chance that you could install it and
run it from the hard drive. The performance will not be good when working from
the Live CD, but it will give you an idea of how compatible the hardware is.
Typical problem areas are graphics cards and wireless. However, many laptops in
particular have more problems than desktops because they have more proprietary
equipment and drivers and settings are usually specifically made to work with
the OS that came with it. That does not mean that it won't work. However, it may
not work as well or you may have to sacrifice some functionality which is
something that you alone can determine.
There are many advantages to using Linux, so keep those in mind whenever you are
making a mental trade-off. Graphics and internet are important, but if
hibernation or sleep mode does not work, then you will have to decide whether
you can live without these or not. Some people don't like making any concessions
at all. Try it and make your own decision.
For a list of Sony laptops and distros that work look here:
http://www.linux-on-laptops.com/sony.html If Ubuntu is not listed, it
does not mean that it does not work, just that someone has not listed
it yet.
Here is a thread on how somebody got Ubuntu to work on a Sony laptop:
http://ubuntuforums.org/showthread.php?t=37469
If this all sounds like Greek to you, then you may need lots of patience and be
willing to learn. This is the worst case scenario.
Or, it just might work perfectly. You never know till you try.