tmorg;
Having taken possession of my new "baby" just last week, I feel your pain on the 25 v 27hp "issue".
Firstly, I'd tell you that I'm in the camp of those that advise that for all but a few, very specific, applications you'll never notice the difference.
But....
...I too spent long hours pondering what I would do should mine come through with 25 (after having waited what seemed an eternity for delivery).
Thankfully, I was spared the decision when my dealer checked the engine tags prior to delivery and it was, indeed, the 27.
For me, it came down to two other "issues" which weighed more heavily than the HP - those being 1) paint job, and 2) getting what I ordered.
The evidence is somewhat sketchy but the number of anecdotal reports of subpar paint jobs on the "older" 25 horse units is large enough to be of concern. To be sure, to some degree it's a case of the older units facing more exposure to the weather but I've been told by more than one "reputable"(?) source that about the same time they changed from 25 to 27 they also changed the painting process/materials. Coincidence???
On the second issue of "getting what I paid for/thought I ordered" it gets a little dicier.
No one but you can weigh the relative importance of the various points of view. Does the "principal" outweigh the "deal"? Is it worth the fight to get what you think you are entitled to (and paid for)? Will the 2hp "really" make a difference in your applications? etc, etc.
From most reports, if you have a written quote which specified the 27, dated prior to the cut off date, you will most likely prevail should you elect to persue that tact. OTOH, it could be anywhere from a pleasant experience to out and out war requiring escalation beyond the salesman/dealer level. Worth it? Only you can answer that.
The final consideration for me was my relationship with the salesman and dealership. Despite the extended delay in delivery, now that it's here I have nothing but good to say about mine. BobCat Inc dropped the ball BIG TIME and turned (IMO) what should have been a "home run" entry into the market to a large bucket of sour grapes over the delivery issues. That, however, was/is something beyond the dealer's control so one cannot hold them accountable.
It remains to be seen, after the sting of the delivery issues wears off, if the "sweetness" of having received a good/great deal on what proves to be an excellent piece of equipment will be the sentiment that prevails.
Best of luck on your decision (I don't envy you that<g>), and here's to years of satisfaction with the new machine.