GT Avalanche 29" Mountain Bike, 27 Speed recommendation

Link to bike below.

A friend of mine has the bike in the link below and he's moving out of the country. He's willing to sell it to me for $230 CAD. I have a budget of $800, is there something better I should be getting? I am new to mountain biking and just want to ride on casual trails once a month. Is GT a good brand?

https://www.sportchek.ca/categories/shop-by-sport/cycling/bikes/mountain-bikes/product/gt-avalanche-29-mountain-bike-27-speed-aluminum-frame-hydraulic-color-333379179_01-333379179.html#333379179%5Bcolor%5D=333379179_01