In theory yes can use it as MDD/MDA however you are likely to need to do some of the transformations/ generations yourself to achieve what you want. Doing this can be a lot of work and not for the faint hearted.
If you are thinking of doing RAD development consider creating the use cases /story boards along with a domain model in EA. Transform the EA model to data model then generate DDL and create a database. Once the DB has be created then consider using a tool like ironspeed or code on time to generate the rest of the stack.
Yes you are right there is no such thing as the perfect tool. EA is powerful and affordable which makes it popular however there is a bit of a learning curve to climb. Its not always intuitive to use. You need to know what your going to do with it and be prepared to put in the hard yards. At the end of a day a fool with a tool is still a fool. There is no silver bullet just a pinch of inspiration and lots of perspiration.
I'd advise you to find a local Sparx Partner to get you up to speed if you are struggling.
Comparing tools - well there are plenty of people out their who try but often there is a hidden agenda or they are simply not qualified to compare tools. Gartners EA tool magic quadrant - would take with a pinch of salt.
Another is
http://www.enterprise-architecture.info/EA_Tools.htm however the last time I looked it was comparing an old version of Sparx EA with new versions of other tools - not quite a level playing field there.
I've also come across vendors trying to sell tools making a comparison of their tool with Sparx EA. After some scrutiny I often find they have blatantly lied. To the un-initiated they can get a way with it but with me knowing Sparx EA for 7+ years use I pull them apart.
If you looking for some kind of endorsement the I can recommend Sparx EA as being the best value tool on the market. I've done lots of research time and time again over the years and found Sparx EA to be good value. Once again there is no gain without pain and that is you need to spend time learning the tool. No short cuts here unless you hire someone to guide you through it.
Well hope that helps in some small way before you take the plunge. In many ways its like standing on the side of the pool thinking should I jump in or not. It feels cold may be not. If you don't you'll miss out on all the fun. Jump in and splash around you'll have fun!
