CATIA v5 is the best-in-class high-end PLM software.
It is very powerfull, but it is expensive one.
CATIA v5 is rather designed for bigger companies.
CATIA is much more powerfull than PRO/ENGINEER
( for example have better surface modules ), but
PRO/E is cheaper and has great parametric capabilities.
CATIA v5 is the easiest for use high-end software.
To cut a long story short:
CATIA is better, but this software is designed rather
for large companies, especialy in automotive, aerospace/defense, railway and shipbuilding industry.
For small business - IMHO - PRO/E is better choice and much cheaper !
Prices in EUROPE:
Catia v5 in Europe cost 13.000 euro ( base version, only
solid modeling ), little stronger version ( with surface modelling ) cost about 18.000 euro. There is
no upper price limit according CATIA v5
The base, simplificated Pro/E cost 2500 euro ( only solid modelling ), The fundamental / primary version of PRO/E cost - as I remember - about 9-10 thousand euro, and full package about 18.000 euro ( much more modules,
features and tools than in 18.000 euro CATIA v5 ! ).
Hope this helps !
PS.
I work for small company that use both CATIA and Pro/E
....and UG and Solidworks

.