I asked tha same question (of myself mostly) as all I'd ever built was a 5w single ender from
http://www.ampmaker.com/ak01x.asp so I really wasn't veru experienced. I bit the bullet because a. I didn't want to wait 12 weeks and b. I have made a few cabinets before so that aspect didn't worry me.
I think if you approach this logically, get a good multimeter, read this forum (and I mean all of it and make notes), print out the layout AND photos to refer to when building, mark each wire on the layout print as you fix it, and you are reasonably practical minded you'll find it a breeze. I was daunted beforhand but in the end found it straight forward and apart from a fault with the OT wiring color coding (Niks supplier had incorrectly connected the blue to the centre tap when apparently industry standard is red) it worked without problem. What I did do though, since I was wary of doing some damage on power up, was to finish it and then pass it to my amp tech to test it and power it up, for which he charged me the measly sum of £35 ($70) Well worth it for the peace of mind.
It took me about 20hours over two weekends to finish it and I would be much quicker if I had to do it again (you don't know what you don't know when you start). Bone up via the net on reading resistor and capacitor values before starting and that will save you hours.
Go for it. You'll get plenty of help and advice here if you need it and you'll have soemthing to be proud of and amaze listeners aswell, it is a superb amp.