When promoting affiliate offers in Adwords: is there a problem (quality score wise) in using the advertiser's url as display url (say: advertisersite.com), but some weird tracking/jump link (say: txflkg.com/click-2098548-234) directly to the advertiser's landing page as the ad url? Any experience?
Adwords does not like any sort of affiliate code. Send them to your own page and mask your affiliate code.
AdWords has no problems with affiliate links that go direct to the merchant. However, the merchant could have a site that is poor in Google's eyes and that can affect your Quality Score. This is especially common with ClickBank merchants, and it is often better to use a landing page on your own site.
Google will only allow one ad with the merchant's URL, which is why you need to send viewers to your landing page URL.
It is also against the AdWords policies to have the display URL and the destination URL on different domains. Definitely, affiliate pages are impacted more heavily with the quality score, so it is really important what you have on that landing page so you can work around it and not get a bad quality score because of it.
Lots of advertisers use tracking URLs - it's not the destination URL that you enter that matters, it's the final landing page (after all redirects from tracking software/CJ). Using the link won't hurt you... BUT, most merchants prevent affiliates from using their own display URL since many of them run their own search campaigns.