What are your views? Theoritically you'll have a bigger market if you have a wider verity of specialised product and services... Like Amway home appliances, LFI nutritional and medical product and services, and venture era's specialized atmosphere product...
imo, it is best to stay in 1 company and focus in that company because when you have a higher rank in the company then you would be earning a lot more due to the bonuses acquired, if you are thinking of diversifying then you will have to do a lot of retailing and have a harder time trying to get leverage from your sponsored downline as the people in your downline will see that you are not committed to one company.
Although some companies do advocate only part -times commitment (may not border what you do full-time?)but to prevent conflict of interest ,perhaps the fine print of respective companies marketting excutive agreement may prevent you for double-hatting,thks.