Which is better? Neither. Depends on what you want.
Like most things in life there's a trade off to be made. Do you want the loudest bass, but limited in range? Do you want the widest range, but limited in volume? Oh, you want both?
Well then, get out the checkbook, because you can't get both for less than $2k, and you might need to spend $4k.
Here are my current subs (JBL drivers only--I have a couple of other brands):
one L8400P (12", sealed, 600W)
three HTPS400 (12", sealed, 1000W)
three FA CSS220 (12" JBL LE120H-1, ported, passive)
four PS1400 (14", dual ported, 400W)
two FA THX400 (14" JBL LE14-H-1, ported, passive)
one B380 (15", dual ported, passive)
That's fourteen subs.
Four are sealed. Five are ported. Five are dual ported.
Seven are 12". Six are 14". One is 15".
IMO, the best is the smallest and the most expensive. It's the $2000 HTPS400, with an Aluminum cone woofer in a 16" cube.
My least favorite would be the largest, the B380 with the 15" driver in a very large enclosure. It puts out prodigious bass in a limited range. It can go neither as high nor as low as the HTPS400, and it's not nearly as fast and musical. But it is more powerful sounding, again in its narrow range, driven by a bridged stereo amp putting out around 1200W.
Most of the guys I know would choose the B380 over the HTPS400; however, most of the guys I know would also buy Bose over JBL or choose to buy beer and miss the house payment if it came to that.
All of these are good subs, but I'd put the HTPS400 at the top, the PS1400 second, and the L8400P third. That's two of the top three spots taken by 12" drivers in sealed enclosures.
I think the 1500 Array with its 1000W amp and single port would handily beat the HTPS400, but at twice the price, $4k, it should. Perhaps soon I will be able to report first hand.
Finally, I've heard (and owned some) Hsu, SVS, Velodyne, Dayton. At the lower market segments, they've consistently drunk JBL's milkshake. JBL ceded the low end by putting out weak offerings. The low end stuff is slowly getting better, but it'd be hard to find anything under $1000 retail by JBL that beats those competitors.
OTOH, with street prices in the $300-400 range, the ($1099 retail) L8400P is a class beater, and considering my own experience with the wonderful SVS PB10 my advice to SVS is you'd better lower the price.