I enjoyed the 12 year old and think it's a great, inexpensive bottle. I've never had the 18 year old, but have heard good things and it's on my wish list (I'm not joking—I do have a wish list and it really is written on there).
If anyone would like to comment on what's good and not so good, the other things on my list are Talisker Storm, Oban 14 year old and Ledaig 10 year old. Really, they're on my list as inexpensive whiskies with reviews that have caught my eye, to replace my current bottle of Glenfarclas 105 when the time comes, so I'm not looking for anything outstanding, just a nice, drinkable whisky.
The HP 18 year old is kind of at the bottom of my list as a 'recommended and want to try' whisky.