Man, its a tough question to answer. A lot of problems finding a partener ie. same strength same motivation promptness dependancy, fire, goals, synch, how well they read your needs............. By self can move faster get more done more time to focus on yourself, freedom to do wkout by natural or instinctive training. I have a great training partner, only problem is he always looks to me to lead the wkout and has a habit of missing wkouts for any number of personal(though real) reasons. I rate my wkouts 1-10. I can reach a 9 alone but not a 10 wo a partner.