with high volume providers the earlier the better but ultimately it depends on  mood , attitude , energy and other variables. An early appointment can make the rest of the day feel better while an evening date is an ideal end for the day. Most working guys are spontaneous or do not plan well in advance so  it is sometimes difficult to get favored slot.    

Most of my appointments have been in the early evening/late evening usually after work. I have always had a great experience. But that being said, it always will depend on the provider.

You will of course run into the popular ones who may be tired in the evening then you will have the ones still fresh.

Being a frequent regular, i try to take into account how the ladies day has been. Being polite, courteous and just plain compassionate can go a looong way.

Beemer

Its not alwyas the best because like you said, you now have the rest of your day ahead of you.

I enjoy dfk and DATY.  The thought that a girl couldve been rimming one of you guys and or sucking down a shot of jiz 30 mins prior to me detracts from my experience.  

Its like using a toilet; do you really want to sit on a warm seat and crap right after someone else, or maybe it nicer to sit on a seat thats had some time to air out.

I've gone for later dates when I didnt care to daty and dfk and was happy enough with those experiences too.  Sometimes, if you have a good connection and history with a provider, you can go someplace to socialize and hang out at the end of their shift.  That can be a lot of fun too because some of these girls are interesting people and you can share some laughs.

Depends on the chemistry

I don't think it much matters, early or late.  I think it's more about he chemistry between you and the girl you're with.  If it's someone that you haven't seen before, the time of day or for that matter, the number of guys she's been with, doesn't really make that big of a difference, especially if there is no connection.