I've had my Spark since March. No issues, no regrets, I love it. There are quite a few misleading statements in the two Yamaha videos you're referring to, and the whole tenor and tone of the videos has diminished Yamaha's brand IMO. I also use my ski's as rentals and have over 60 hours on both of them.
The biggest ill-advised statement in those videos to my mind is when the Yamaha representative says a tank of fuel "might last for an hour or two" on the Spark. That's a ridiculous statement. If they were really serious about convincing you how good the VX is against the Spark, they would list some fuel consumption side-by-sides. They didn't do that. For me, as a buyer, I'd be interested in them crunching the numbers. But they don't do that; they make jokes about plastic water bottles and the chill shade instead.
Before I looked at the Spark, I was looking around at Yamahas. Everything I read indicated that Yamahas were renowned for their reliability, and that attracted me. But then the Spark came out and I could buy a brand new machine under warranty, still have money left for insurance, safety gear, and accessories.
Another point Yamaha criticises the Spark for is the add-ons. But for me this was a good thing, because there are only some things you have to buy upfront (i.e. choosing between 2 or 3UP and IBR). The rest you can add later when your cash flow allows. So it allowed me to only have to save a certain amount of cash for the upfront purchase. Since I got, it I've added mats, the step, the storage bucket, side bumpers, etc.
They also criticise the Spark for its 'plastic' construction. But the upside of this is the weight of the machine. It can be towed by a very small car. So if you've got a small car, you don't need to work a tow vehicle into your budget as well.
I think you should consider why Yamaha would upload videos like this to its official branded Youtube account, without any statistical or scientific data to back what they say. They have never done this in the past towards other ski's or jet boats why now?
If Yamaha had a good story to tell about the VX, then that's what they should have done. For them to invest dollars into producing videos like these shows they are more interested in talking about what they think their competitor is doing wrong, rather than what they think they're doing right. As a potential buyer, you should think about that.
The other thing I think was a misjudgment by Yamaha is assuming a potential buyer might look at these videos and do no further research. These days, when I'm making a 'big' purchase I look around. It doesn't matter if it's a new TV, a microwave, or a car -- I research it online. I see what people are saying about it, I visit multiple sites. I don't just trust one opinion straight away, I read as many as I can. Given you've even posted the question in this forum, I can see you're the same. These days, most people are.
The danger for Yamaha in this, I think, is that they risk saying to potential buyers 'the Spark is bad'. But if those buyers ultimately choose a Spark and find that it's actually very good, when it then comes to their next ski purchase they'll remember Yamaha for the wrong reason: that Yamaha is willing to peddle misleading information for a sale.
LETS COMPARE A FEW THINGS
So first I am only going to compare both models.
So 2up HO Spark I paid $14,200 ( this is for 2 and double trailer + TTL) so $7100 each. for the Vx base model, and after the transportation fees that all dealers add on, and the trailer, the Vx will be pushing that $9,500-10,000 dollar range. Now lets get to the fuel usage, and tank size, and how many hours before your empty. Spark has a 7.9gal tank, uses 2.4 gal per hr at 35mpg, meaning you'll be empty in just over 4hrs. And will cost you roughly $30 to fill up. The Vx has a 18.5gal tank, uses 4gal per hr at 35mph, meaning you'll be empty in 4.6hrs. But it will cost you roughly $70 to fill up. Hmm so I can save $2,400-$2,900 with the Spark and could use that money to fill the Spark 100 times.
But, the Vx has 110 hp and the Spark only has 90 hp so you will go faster on the Vx. Really!? How much faster? Being $2,400 more than the Spark it better be much, much faster. Nope, sorry Vx you have a top speed of 54mph. The Spark has a top speed of 48-50mph at 90 hp. Really!? the Vx only has a 12mph advantage. So you pay $2,400 more for 5 or 6 mph?? Doesn't seem worth the extra dollars to me.
But wait, how come the Vx doesn't have a top speed in the upper 60s or low 70s? Oh ya, the Vx weighs 736lbs. The Spark weighs only 405lbs. Ok, ok lets be fair the Vx can carry 3 people while the Spark can barely hold 2 adults. But, I didn't buy a jet ski to be a chauffeur and give people rides around the lake. And your not going to throw tricks with 2 people on the PWC, so who cares. But, the Vx has 15.1 gal of storage space, and the spark only .42gal. Again, what do you need to store? Remember your only going to be on the water for a max of 4.6 hrs before you need to stop and refuel. Which means anything that you might need to store can just hang out at the beach with your other friends or in your vehicle.
I've owned the yamaha LS 2000 great boat never a issue, also had 2007 ar210 motor blew in less than 5 hours some of you might remember had issue with yamaha and they refunded me all my money back. I then purchased the seadoo challenger 255hp great boat never had a issue. Ended up using it to tow a yamaha in at the yamaha gathering a few years back after they hit a sand bar. Only issue with seadoo was the super charger rebuild every 100 hours. Only reason we sold this boat was to upgrade to a bigger boat which is the sx230 which i still have and love. Also to date the vx is by far the most used rental JEt ski out because of reliability. I can't say that the spark at this point is better than the VX but i can say when you go into the dealership and compare both side by side it's hard to purchase the Yami hands down anymore. It a reason why most dealers are running out of sparks very quickly. I think it's to early to write the spark off also.