I know for myself, Cardis are longer and heavier and since I thought I might want to try agility, I was a little put off by the height/length proportion of the Cardi.
I believe, though, that the Royal Family helped propel them to popularity. Cardis are also generally thought of as a bit more stand-offish with strangers, whereas Pems are viewed as being more outgoing, and that has something to do with it too. When you look at the popular breeds, most of them (not all, but most) are the more outgoing dogs.
I feel that pembrokes are definitely a more known breed than the cardigans. I have heard that cardigans are more reserved with strangers than the pembrokes, like Beth said. Cardigans are still very friendly, they just want to know you first, before they trust you, whereas pembrokes don't worry about it.
Our cardi, picks and chooses who he is more reserved with. There are times we are out on walks and he insists on going to say hello to people he knows and then there are times he insists on going to say hello to people he doesn't know(pulling me into their garage, (if thats where they are standing), can't figure that one out. Then there could be someone randomly walking he gets all concerned about, no rhyme or reason.
We have had our pembroke for about 2 1/2 months now, and Tucker (pem), is soooooo relaxed!!!!! Get this, even with the scary vaccuum monster. Today he just walked right by it while I was using it. Lance, usually moves to another room. I truly am amazed how calm he is with everything, after all he had been through before we rescued him. Lance runs around alerting us of all the activity outside, kids playing, dogs going by, you name it, Lance zooms by Tucker just lounging around on the floor or him standing still looking at Lance, like whats the big deal. lol.
They both love attention, love food and are both huge tripping hazards!!!! If you aren't watching where you are going, they are right under your feet. I would have to say in the last 2 1/2 months we have had Tucker, hes tripped me quite a lot in the small time frame we have had him. I find Tucker wants to stay by me at all times for the most part, where as Lance is a bit more independent, but also likes to spend quality snuggling time with his family. I guess it works out well that Lance is a bit more independent, he doesn't seem to mind that Tucker stole his spot under the computer desk when I am sitting at it. Lance has definitely been a tripping hazard over the last 5 1/2 years but not quite as much. I love having both a Cardigan and a Pembroke.
One of the main differences in body styles I noticed besides the size in length and the ear shapes, and tail vs no tail was how flat Tuckers head is compared to Lances boney head. Much nicer to pet the top of Tuckers head. :)
I have three cardis and I adore them. Cardis are, as a rule, more mellow and laid back than pems. The pems seem to be much more high energy than the cardis. While they need alot of activity like the bunnybutts, they're happier to also chill out and be a couch potato, too. More so, I think, than the pems. Cardis are also roughly about twice the poundage and size than the pems.
Of my three, one (Nimh) is a therapy dog and definitely not standoffish, another (Annie) is also very very very friendly with people as soon as she sees them. Teri is a bit standoffish with folks she doesn't know but it doesn't take her long at all to get to know folks and then she's not shy at all. Teri and Nimh both love agility stuff and do well at it (just for fun, not competition). Annie is a natural born herder.
But when it comes right down to it, both cardis and pems are awesome dogs!
This is my clan back in xmas 2010.
L-R: Wife, Sis, Bro
L-R: Vienna, Amie (Fluffy Cardi), SamSam (Cardi) and Mocha
Pick your Cardi Tails: Bushy or Regular?
To answer your questions:
1. There are more pem breeders in NA than cardigans. To give you a perspective, most cardi breeders know other cardi breeders, yes, the circle is THAT small. Good thing is cardis are bred better and controlled in NA compared to pems.
2. Cardigans do get much love, but more in a fraternity / Justice League, kinda way :)
3. Nah... try crashing a pem meetup party with a cardi, you'll be an instant celeb!
In all seriousness, after living with both. I find:
1. Cardis are easier to read (Tail) than pems (No Tail), I really do think that pems are often misunderstood by other breeds at the dog park due to a lack of tail.
2. I find Cardis are more protective, when I walk all 4 together, the cardis will bark at strangers first, the pems will lick first and ask questions later. However, a few minutes later, the cardis will warm up and join in on the kiss fest.
3. Cardis costs more, eat more, weight more, poop bigger, require higher dosage rx, bigger longer crates. Cardis has a deeper bark, if you are living in a pet weight restricted rental complex, it'll be harder to fly under the radar.
4. Pems have fewer color combo to choose from.
5. Cardigans are Loyal, my pems are chronic adulterers, they cheat on me all the time - both human and canine.
6. Cardigans have fewer but better, more protective breeders in NA, since the circle is small, rescue situation are few, everyone knows everyone, you'll get the support you need. Of course it can go both ways.
Met a Pem with a lab-like tail yesterday; it was expressive! A rescue.
Al does have a problem with other dogs sometimes. Seems he doesn't know how to say "Back Off!" politely, and ends up snapping/lunging. I think he'd find a tail useful.
Sam has a lot of really good points. I think a lot of people find the pembrokes to be "cuter" if nothing else. Cute foxy face, cute smile, cute bunny butt, etc. Pems also seem to be thought of as good apartment dogs where as the cardigan seems to be labelled more of country dog, but in my experience the cardigan is more laid back and very easy to live with.
Cardis are bigger but I wouldn't consider them to be twice the size of a pem - standard for a male pem is 27 lbs and for a cardi 30-38. There does seem to be a trend of oversized cardis at the moment, but it seems like a lot of breeders are realizing this and trying to get away from it. My cardi Luke is only about 27 lbs at one year so I expect he'll end up at the very low end of the standard once he's filled out, which is totally fine with me.
Personality wise my cardigan is definitely more wary of strange people/dogs which does require more management than my uber friendly pem. Around here everyone has labs or goldens so if your dog isn't immediately friendly they seem to think he's mean. Luke has a BIG bark and isn't afraid to use it, which can be annoying/embarassing in public, but I can guarantee no one would want to break into my house if they heard it. Henry would probably lead an intruder right to the electronics, lol. I would say Henry is quite a bit smarter than Luke but he's very "what's in it for me" and "ooh random stranger, must lick!" where as Luke is very eager to please and focused on me, which makes him easy to train.