I never heard the 4010; however, it was highly praised back in the day. I believe it's bipolar outputs and I prefer mosfets as they are tubier sounding. $800 seems high for both as there are a bunch of $300 amplifiers here and on Audiomart that are on par with the Robertson if not better sounding. Currently there's a Hafler 220, Perreaux PMF1150B, Musical Design D75, Apt Holman, and PS Audio Delta 100 from $200-325 that I would also highly consider. There's also an older PS Audio Model Two on A'gon for $225
As far as the preamp goes, the IVH was the later better model but I would be on the lookout for a 4.6, 5.0, or 5.5 as they were all better than the IV. Years ago, I auditioned the IVH and the 4.6 and almost bought one of them but ended up getting a tube preamp. For under $400, the Dyna PAS3 is hard to beat - very musical.
I think you have to be a little wary of reviewers and trust your own ears. The old Hi Fi Heretic magazine rated the British Fidelity B1 int amp as one of the 10 Best Buys in Audio back in the 80's. The other contenders were the B&K ST140, Spica TC50s, ProAc Studio 1's and other popular items. I got the B1 integrated and ran for the hills it was so in your face and annoying sounding. I also heard it after I sold mine with other speakers and still was not impressed.
Keep us posted on what you get and how you are liking it,