I've noticed with my vortechs one is significantly noisier than the other, being as I bought them quite a few months apart one was the original the other came with a wireless driver, so it seems there might be some slight design issue involved with the added noise or that their manufacturing methods aren't very uniform across the board.
However at 75% of the total power it's almost dead silent, that being said it's ALMOST silent, so in a pulse mode it's not surprising that you're able to pick up on the sound differential, especially if it's in a visited room like a living room.
One thing I don't like about them is that you HAVE to buy them with a controller now, which tosses $75 onto the price, compared to a tunze, that's more expensive, however if you're using 2 or 3 pumps you don't have to decide if you want to continue to buy single controllers or a multicontroller. That being said I don't care for the wireless aspect, it's nice and all but apparently is severely limited in that it could have very easily gotten away with a wired version, so it seems more of a bragging point than a useful point.
If you have a large tank, with a thickness of 3/4" or over these are not for you though. Sure you can always build a dry box for them (see EcoTech/DIY forum for someone who has them), but do you want that extra bulk in your tank?
I think you could get away with either there are pros and cons to both. Thing is Tunze's 62xx stream is packed with lots of power that Vortech can't touch, so if you want massive flow (at a massive cost
) might want to go that route.