Shimano 105 5700 in 2019
This is very much opinion based question. I'd say that 5700 is still above current day Sora and a very solid choice indeed. I'll also argue with some of the comments that 10.5kg is heavy, especially at the price point of 300 EUR. As a comparison Triban 520 RC (praised to be extremely good value alu/carbon bike for packing partial Shimano 105 groupset in 750 EUR) is 10.3kg. There are very few bikes under 9kg that cost less than 1000 EUR and probably none under 10kg for 500 EUR or less.

Actually, at this price point, this is probably way above anything else you might be able to get.