As Adrian says, the HP rating of the AC brush motors are a bit of a "stretch". In fact if they made them less efficient (and drew more amps) they would advertise more HP.
I have done some real world non scientific testing using an HSD 1.0kw (1.34hp) 220V spindle vs 3.25hp PC and Milwaukee routers. Tests were done with a 1/2" bit, 1/2" pass depth in MDF. Feedrates started at 50ipm and increased by 50 with each pass. The results were charted at max rpm for all. Then at a percentage decrease based on router "presets". Another test was done at equal rpms.
Short answer was that at max rpm on both the little spindle was able to push the bit 25% faster than any router. That percentage that the spindle was "stronger" increased as the rpms went down. At lowest RPM of routers (10k rpm) the spindle was able to push the bit at double (or more) the feedrate that stalled either router. You can assume that would be 4 times as fast for a 1.7kw (2.2hp) spindle, slightly less for the 1 hp like Scott mentions.
In any case the mini 65mm 1.5kw Chinese spindles (I have owned and sold 3) will easily outperform any handheld router in the 3+hp class. The ones I had were shaft fans, which are noisier by far than an HSD fan cooled, but much quieter than any of the routers. The Milwaukee being far quieter, and slightly more powerful than the PC.
All in all, I have personally purchased (and then sold in a package) 13 Chinese "air cooling" spindles, some fan cooled, some with shaft fans. I have not heard of a failure. I do not use the generic cheapo eBay VFD's. I purchase from US brick and mortar suppliers and the VFD's are programmed properly, which along with cheapo water pumps on the water cooled versions, is a major source of spindle failure.
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