I'm not sure if I can say that your tracert looks similar, but how you described it definitely does.
I've tried a Motorola SBG6580 (purchased on my own) and an Arris DG860A (provided by TWC). I actually purchased the Motorola since it had some of the best reviews and I was hoping it might fix (or somewhat alleviate these issues), but no luck. The Arris seems slightly better even, but both have the same issue.
Here is a graph of my 2nd and 4th hops: »
i.imgur.com/jibQ4Hh.pngThe 2nd hop shows some crazy spikes that I don't fully understand, but they happen 24/7 and don't really correspond to any kind of performance hits that I can feel while gaming, so I haven't been too concerned with it.
The 4th hop is where the performance hits are noticeably visible and do correspond directly to gaming performance. But as I mentioned before, the different modems will report them at different hops some reason (maybe just a flaw in the PingPlotter software?). On the Motorola, the nightly spike was not visible at hop 4, but it was at hop 3. The Arris reported lag at hop 3 three nights ago, but it has reported it at hop 4 for the last two nights.