It's a personal preference. Sounds like you are a naturally skinny guy. It's easier to lose the fat than gain the muscle. Seeing your numbers go up is a confidence booster for me, makes me feel like a badass. I lifted for strength last year and felt amazing despite noticeable aesthetic gains, now I will go for size this year because I want my clothes to fit better.
“Only a fool learns from his own mistakes. The wise man learns from the mistakes of others.”-Otto von Bismarck