IMHO, the horse in the first vid is carrying his head a bit low for his own ability. It appears that he's having a little bit of sporadic trouble really engaging from behind, which makes his lope choppy in some spots. BUT, I suspect that's more than just the low head carriage. There are a few other things that pop out as being sticky like him having trouble keeping his pivot foot planted in his spins. Whether that's because he's being maintained by a non-pro, something lacking in his initial training, or his own physical ability, there's no way to tell.
As Sorrelhorse said, the low and slow is the "in" trend right now. Look at any of the big names like Craig Schmersal, Shawn Flarida, Tim McQuay, etc. Most of their horses carry their heads down a tucked. I'm not a fan of the fad, but I can't say that I would be ashamed to throw a saddle on any of their horses either LOL.
With my own experience coming from a ranching type background instead of a showing background, I tend to think in terms of what's functional rather than what's fashionable. For that reason, I really prefer the carriage of the second horse better, though he has a few sticky spots of his own. He looks the type that would be ready to win in the ring and then go out and work cattle the next day without missing a beat.
Here's a better example of a horse that carries himself low but still has good engagement behind (I love
BCTC anyway...even if he is a little frustrated LOL)
Personally though? I think this is one of my favorite horses of all time. He's forgiving of rider error, he knows his job and does his job...sometimes in spite
of the rider LOL. BUT, I'd imagine that a horse like this would be out of most folks' budget
The biggest thing that I don't think people think about when first buying a well-trained horse like that is the upkeep. If a person doesn't have the ability themselves to do tune-ups, then they're looking at spending thousands of dollars a year with a high level trainer to keep the horse sharp and up to level. If they don't, then (forgive me for saying it like this as it sounds rude but that's not the way I mean it) the horse will end up "dumbed down" to the level of the rider. Their handle and their carriage and their changes and their gaits will start to get sloppy and inconsistent.
Would a novice starting out be better with a 7 year old rather than a 3 year old?
That depends solely on the horse. Like I said, most riders are still looking at thousands per year to maintain the training and/or have lessons themselves to maintain their riding. For that reason, IMHO, it's solely dependent on the horse's temperament because any training issues will be addressed by the trainer. A kind and forgiving 3 year old would be better for a novice than a testy and demanding 10 year old, regardless of experience.
Of course, though, if a person could find a kind and forgiving older horse, they would be ideal