Well for $300 u wont get anything really good.

I would try a ASH26 4 meter is a good glider and should fit your skill levels. You will be able to do some loops rolls and stall turns if u want to go more in to aerobatics you will have ot get a Salto or Fox. The ASH is a good glider for termaling and slow aerobatics.

Also the DG600 is a exelent glider with a very good speed envelope and capaple of some aerobatics

But planes in the 4 meter class u will have to spend a little more than $300 by the time u are finish with the plane u will have $1000 + deoending on your outfit.

Icare has some good gliders have a look. Nordeast sailplane is ok but I dont like their quality.

I normally import my gliders directlly from the manufacturer in germany. It is a little costly but u get good quality.

Im just finishing a DG505 from

http://home.t-online.de/home/modellbau-schueler/

It has 6.29 m wingspan and taking the wingtips of it becomes the aerobatic version of the DG505 so I have the best of both worlds. But for a price.

Saludos Landi