Differences between netdate, ntp and chrony ?

I want a simple task performed. ntp does it, but is not really made for a
dial-up system like mine.
                                                                                             
chrony does it also, but what I wondered is: couldn't It use netdate for this?
                                                                                            
I have put the following script in my /etc/ip-up.d


#!/bin/sh                                                                                   
if [ -x /usr/sbin/netdate ]                                                                 
then                                                                                        
 /usr/sbin/netdate 165.91.52.110 > /dev/null 2>&1                                            
fi                                                                                          
exit 0                                                                                      

         
165.91.52.110 is a time server.
                                                                                            
In /etc/cron.daily I have this script:


#! /bin/sh                                                                                  
if [ -x /sbin/hwclock ]                                                                     
then                                                                                        
 hwclock --adjust                                                                         
 hwclock --systohc --utc                                                                  
fi                                                                                          
exit 0                                                                                      

                                                                                            
This last script is there since I do not often reboot, and still want the
hardware clock adjusted.