Tenerife has better weather and you're going to notice if you're staying for more than a short while. That makes Tenerife a hotspot of tourism, especially around Playa de las Americas/Los Cristianos.

I recommend less touristy places, but stay near if you like parties. Los Gigantes is cool and cheaper a bit.

I never really stayed for long on Gran Canaria so I can just say it is nice.

No contacts unfortunately, I'm not staying there permanently and when I do I just work with my clients from mainland EU.