Having a Gaas-fet really has no bearing on being a good preamp or not, it depends on a combination of gain, noise figure, IP1 and IP3 ratings. Gaas-fets can have lower noise figure than similar silicon based transistors but many are way too small to be used as a wide band preamp without preselection.
The majority of wide band preamps I've seen lately run a little dinky RF IC that can be Gaas or silicon but are also too small to be useful, they amplify but also generate tons of IMD due to being run into oblivion from overload.
Angle Linear makes some of the best preamps when it comes to being overload proof and having the proper amount of gain and low noise figure for a particular application. These are almost always used after some sort of preselection even though Angle Linear preamps are more overload proof than most anything on the market today.
To date they have not made a wide band preamp (over about 200MHz BW) due to the hurdles of marketing an amp that will meet their goals of giving the customer an amp that will not fold when hooked to a broad band Discone like most other preamps will. Rumor has it they are working on a wide band preamp for our hobby but nothing has been announced yet.
prcguy
Gallium arsenide field effect transistor,(gaas-fet) is the heart of a GOOD preamp used to boost radio signals,but most of your run of the mill preamps won't use them due to the extra cost.
Remember; you won't be a newbie forever! Hang around us here at RR and you'll learn things whether you want to or not! :lol:
Good luck!
n9zas