firstly this is totally in my opion
hardest part about changing from a hardtail to a XC FS bike was the bottom bracket height. yup, not the small amount of pedal movement (not really bob), you get used to that fairly quick & most decent shocks have really reduced any bob these days. The higher BB height really alters the feel of the bike, esp in slow speed corners, thats the hardest part to get used to.
I took curlys patriot (140mm forks, 6in back end) out to the french alps & was amazed at how well it climbed. for extended road climbs lock both ends out.
on real steep climbs (I live 1/4mile from a 1in4 climb) yeh the front end wants to lift, but thats more to propper body positioning than fork height.
I rode fully rigid from 85-95 & hardtails from 95-01 (intense tracer was a mistake!). aside from glass smooth trails quality XC FS bike will always be quicker/ more confidence inspiring/ more efficient. Luckily we've finally reached a point in MTB evolution where XC FS bikes are fairly reliable! yeh it does take a while to get used to the non road bike instant power transfer of a hardtail. but I'm now converted & once you go through the intiation process theres no turning back (anyone want a titus titanium
I'll still ride hardtails & fully rigid time to time. on the 1% of glass smooth trails they are enjoyable. maybe i'm gettin old? I just want to ride as far & fast as possible with the least effort!
Anyone who ever wants to meet up for a ride my way are more than welcome.