I’m not sure quite what you mean by sharing experiences, but I’ve submitted to Harlequin for years. I have yet to break through, though. I usually aim between Desire and Special Edition. I’ve been asked for revisions twice. I have a manuscript right now that I just did requested revisions for. My agent just sent them back a couple of weeks ago. Lately the wait times getting back have been longer. Before I found my agent, I waited for a year and a half only to given a rejection. Luckily, I’ve always gotten feedback, though, and the editor always asks me to see more. I think I’ve only ever gotten one form rejection.
Anyway, again, I’m not sure what you’re looking for in a response, but that’s been my experience so far. Seems a very hard corner of the market to break into, simply because their needs are so find-tuned. The revisions I just did were a couple of plot points she wanted changed and fine-tuning the manuscript to better fit the Desire line.