In the beginning I got updates every few weeks.

Now the phone keeps saying it would be up to date with this update:
Android 7
V0.1 _29170803_20171011-0929
Security updates of 05.07.2017

In the forum there are a lot of ROM`s to download.
Which is the best to download ?

The later the better, but if your device works flawlessly there's no need for a firmware update
Remember that sometimes some devices don't get every OTA update. This is annoying, but considered as normal.