i actually find it to be very helpful. there are two main differences between this and the spare parts catalog covering 40-50 solos and servis. the first is on the right hand side of each page it lists whether the part is for a 40 wla, 41 wla, or 42 wla, or all of the above. so if you have an earlier model it is very helpfull. the main advantage is the indexes in the back. all the parts are cross indexed so you can find tham by part number, govt ordinance and stock number, or govt group number, as well as an alphabetical index. this is helpful mainly when it comes to nuts bolts and washers. if you look in the regular manual you have to find where an 0107 nut goes by looking at all the pictures, and hoping you spot it. but with this manual, you look up 0107 and see it is only used on the ubolts for the coil. very helpful to decide how many you need to buy per bike. as for price, i've seen repops go much cheaper and originals go for more.