Wow, tempers are running high.
First of all, it is not a match violation for anyone to tell me exactly (or vaguely) where my program will be ranked. You are free to tell me I am your #1, that you won't be ranking me at all, or anything in between.
Equally, I can tell you whether you are #1, #1001, not on the list, etc.
What you can't do is ask the other person, nor make any deal such as "I'll rank you high if you rank me high". So, asking "Where am I ranked?" (by either party) is really not allowed.
Now, back to the original question. How helpful is "I am ranking you highly"? My sense is -- not helpful at all. Because, what does "Highly" mean? Probably not #1, or you would have told me that. Maybe top 3? or top 5? Or top half of your list?
This is exactly the same as an email from a PD that you are "ranked highly". Getting such an email is clearly better than one that says "we're not interested", but certainly does not guarantee anything.
The most controversial statement by PD's is "ranked to match". This statement also has no uniform meaning. To some, it means that if a program has X slots, you are ranked in the top X slots on their list -- this would mathematically guarantee a match if you rank them high enough on your list. To others, it means that you are ranked high enough on their list that, historically, you'll get a spot. But, we've all heard stories where someone fails to match and then is told "Oh, well, we filled much higher than usual this year".
Telling me that you've ranked me #1 makes me feel all warm and fuzzy. Still, people have told me this and then matched elsewhere (they were high enough on my list to match with us). In my book, no hard feelings. The match is all about being selfish -- rank programs you want to go to highly. If that's somewhere else, that's fine with me.