always buy the best, and always buy brushless generators.(self exciting)-waukesha engines with kato generator ends are the best on the market today for reliable power- it will cost alot more, but it will last you a lifetime- and the resale will be very good many years from now, even used..
http://www.kraftpower.com/equipment/attachments/96/VRG330-6217.pdf
http://www.power-technology.com/contractors/powerplantequip/kato/