All AEG function the same or based on Tokyo Marui V2/V3 gear box, try a TM MP5 or a CA MP5 they can be bought cheap now, avoid the clones of clones the saying buy cheap buy twice can't be more true. you can make any AEG perform it depends on how deep is your pockets and what parts you put in. Avoid GBBR or TW platform as your first unless you have use it in the past or have some basic knowledge on them TW platform are great but the price tend to scare off a lot of newbies, GBBR are like Women on the rag if it work well DON'T TOUCH IT! some have great experiene with GBBR but most have a bitch of a time with them but they are a hoot to shoot.
Ultimately the best advice you can take is settle with the gun that meets your criteria in fit, comfort, performance etc. different opinion do matter but in the end the choice is yours.