Some of the points to consider are:
1- availability of parts (be it from your local LHS or mail order or net order (helps when you have a mishap and break something)
2- the availability of assistance (your choice may be a more problem prone then something else, so it will help if you have someone locally that has had the same problems and solved them). It also helps if you have locals who can help you with the initial heli, radio and engine set up.
3- the dependability of the units - the few problems you may have to solve with the heli (e.g clutch systems that are prone to early wear and failure, rotor heads that are more susceptible to blade flutter, engines that wah-wah, mufflers that are loud. leak and/or break, support struts that may have a tendency to break, swashplates and other parts of the control system that develop excessive play early on will still fly but will greatly increase the workload on your two thumbs and slow your progress.
4- the durability of the unit - the fewer the parts that break in a crash the easier it will be to fix and probably the lower will be the cost to fix. If brand A has less expensive parts but the lower mainframe breaks more easily then brand B then it may cost more to repair as you will have extra parts to buy.
5- the cost of parts - in conjunction with the above will reflect on the cost of the repair
6- cost of maintainance - the less dependable units will have higher maintenance costs in both money and time. The money and time spend replacing clutches for example can be considered with the cost of repairing crashes.
7- running costs - here the 30 size come out way ahead.
8- short term to long term costs - a heli that is relatively low priced and can easily be set up to be trainer stable in the hover and later be set up for hard 3D and aerobatics before wearing out or needing expensive upgrades will offer both advantages. Ditto for radio, gyro and engine /exhaust combinations

I use to have a raptor in 2000 but it has a so strong woof and poof... and since nothing seems to cured the problem (i changed so many parts in it, it cost me a lot in time and money) : as a result I do not really fly much in 2001, add the the very bad weather (it was raining everytime during week end). A friend decide to buy a moskito (he has the same problem with his raptor) and i did the same too (bought in UK for a very low price). Then a futura entered in my fleet but only for 1 months. I was too scared each time i was flying : what would cost me a crash ??. In february 2002, I buy another used raptor 30 with alot of parts for a very low price, then found the eraptor and the heaven on ebay........I will stay with the raptor and I know some pilot who now resells their futura or millenium : too expensive : a crash with a Robbe Millenium can cost you 2 raptor kit 30 ARF!

Now I must admit, that i do the same mistake as many pilot : I upgrade my machine too much. "take a good exhaust", "add a metal part here : less slope". "change this, you need better servo" As a result you have a machine who cost nearly 1500€ !!!!! but know I recover my mind, and exchange all parts, gaining 5% or less with a better exhaust at 120€ is for me now crazy: a crash and you lost everything...... so keep your raptor stock ! Robbe and other compagny should reduce their part's prices. Do not try to follow experimented pilot or people who are doing competition: they do not always pay their heli... (free from manufacturer)

Tips :

• Flying heli is fun, but it is even better if you fly a cheap and easy to repair heli, forget high-end heli with lot of upgrade or carbon frames, forget 60 size for everyday flight.
• Choose upgrades that can increase SECURITY of your model and persons, nothing else. Upgrades part can break or usually bend in a crash (metal swashplate....)
• You can increase security by only changing some parts in your heli or following some advices/tips from experimented pilot or forums.
• A crash can occur at ANY TIME, don't play poker with your life ! always sacrify the heli ! it is just a mechanical toy and you can buy many parts to repair it, it is not the case for your body or for replacing killed people.....
• Cause of crash in increasing order : external events (birds, collision with airplane) -> mechanical failures -> radio glitches -> pilot MISTAKES