[Sony Xperia P, U, Sola, Go] The_0bserver:
I really doubt that could happen.

Check this thread. I got it by googling the words "how to use flashtool xperia sola". First result in the first page.

First off it looks a lot different. as in the stock based ROM u will generally be using the Timescape UI (Sony's Launcher that you get in stock). Which isn't what you get in Cm based ones -(Trebuchet I believe.)

Also in the stock based ones, you will still probably be using apps such as the Sony Walkman app, , the Sony Album app etc. Whereas in the CM based ones can be practically anything Such as Appollo for Music or even getting the Walkman App back again, or else walkman apps of different phones (example Sony Walkman and album/movies app from Xperia V).

The modded stock app will have a quite a bit of the absolutely useless apps that were preinstalled by sony removed. CM based ones will have even more of such useless cluttter removed. hence resulting in a much lighter ROM.

On the side of things, CM is generally faster(aka better performer) and you would get a better chance at modding as there generally is alot more content that you can grab.

Also sometimes the CM folks add some really nice stuff to the mix,which really help that cannot or will not be added to the stock based ROMs.

On the bad side for CM versions though is that - You cannot run softwares such as PCC/ SUS (Sony Upgrade Service). You will have to manually flash the ROMs (which once you figure out how to do it, this becomes a much better and easier and less time wasting option as compared to PCC/SUS).

Also Most of the CM ones are still beta builds, so make sure to read up in the threads to see if there is a feature that you would really require that has not yet been added/fixed. Example -XU CM ROMs (FXP/theBrainKafka's FXP ROM etc) still does not have some features such as Radio (the actual radio-like the one you use in a car) and A2DP. -Agreed both of those aren't features that most consider of much use if any. (I don't but i know a few ppl that consider those options as deal breakers). Also sometimes some stuff such as the illumination bar is buggy/ broken . Though generally is fixed with 1-3 days after launch of the FXP version.

And lastly for the CM based ROMs,you will nearly always need to have your Bootloader unlocked... there are versions out there for Locked bootloaders also (example FireDroid for XU), but they tend to be behind in terms of development as compared to the normal (BL unlocked) varieties.

Battery life can differ- though for me CM ones have been much better than for stock ones.

Speed -I saw a serious speed boost for CM ones... I've litterally not experienced lagg on my phone once I installed CM ROMs.

Camera App - Some ppl love it, SOme hate it. I don't really see much change -though I'm not particularly a camera person.

GPS fix - generally the stock ones had a better a GPS fix.. (Only for Sony devices - Somehow Sony hits things right for GPS). Though some builds such as the Brainkafka's ROM has a similar/equal speed. (note that this changes based on what device you looking for. For example -my sister's micromax a110 canvas2 takes forever to load the GPS co-ords on her stock phone.)