14 kg is a lot to carry any distance, especially if you have other things to carry. It's also a lot to maneuver into tight spaces on public transport. I've bought a couple of Chinese bikes in the last few years and found they are very stingy with the low grade grease they use. I immediately replace the grease in bearings and headset with higher quality grease, and as I found none at all in the bottom bracket threads, greased the threads generously. Makes it a lot easier to pull later. Applying grease in the seat tube can also be a good idea unless the directions (A la Brompton ) say not to. I'd also check everything closely before I went home with the bike. Such things as brake pads out of alignment on the rim, wheels out of true or wheels not spinning freely due to overtightened cones should all be fixed gratis before you take the bike home. Lastly, ride the bike some distance before you buy it. I've found that quite a few bikes that look good on the net or even in person, were unpleasant for me to ride although fine for others and vice versa. Good luck with your new friend.