At home I've got both cable and ADSL internet access. The original intent was that the ADSL access would replace the cable since the cable was at the time being run by one of the crappiest ISP's I've ever seen.

However, this ISP (much to my surprise) changed it's policy considerably and now all is working fine. Unfortunately by that time I had already signed a contract with an ADSL provider for one year. This ADSL ISP is top-notch, I've dealt with them in the past, but because cable is still faster than DSL I'm now still using the cable as my primary internet connection.
I've tried using the two connections on one pc using two NIC's, but the kind people on this board pointed out to me that this wasn't going to do a lot of good (and it didn't) and so from that day on the ADSL connection is being used as a backup for when the cable goes down (which used to happen a lot more in the past than nowadays, but still...)

But today I stumbled upon this product. It's a router made by Longshine which has two input WAN ports. It allows for two WAN connections to be connected to it and to be used simultaneously (using Load-Balancing). I believe that with this product it would be possible to use both my connections on one PC, effectively almost doubling my bandwidth.
I only have one doubt : the router is being sold as an ADSL router, but in it specs (posted above) it also makes mention of cable. To be able to use it with cable all it should have to support would be Dynamic IP anyway.
The price isn't too bad either. I could get it for about $140.

So do you guys think that what I want this product to do is actually do-able? Or is it designed for two ADSL connections and is there no way that cable will work? Is Longshine a trustworthy brand? I've never bought anything from them in the past but I have heard of them. Do competing products for this exist? (I've never seen anything before that does this too)

Thanks!