I think the best solution for you is to have ERP systems integrated like Sage 100 in your main shop. You can find more infor about that here - https://en.wikipedia.org/wiki/MAS_90 . That is giving a full pack of features available for easy marketing.
After that I suggest to check an extension developed by Information Integration Group. That have amazing features for that integrates seamlessly with and automatically synchronizes data from your Sage 100 to Magento Enterprise or Magento Community e-commerce store front.
You can check more information about that extension here - Magento integration for Sage 100 .
Hope this will help you to find the best solution for you. But I think it is!
We've found the IWD extension to be a little glitchy as-well, but with a little love and tenderness you can get it working well. you can see it in action here
From our experience the onestepcheckout.com extension seems to be the best in terms of support, reliability and features but it comes at a premium.
Same here. I use OneStepCheckout.com mostly because It Just Works.
Thank you so much for mentioning us. We are glad you've used our extension successfully several times and we hope that you and your clients continue to be satisfied with our extension and the support we are providing.
Thank you for sharing your experience. We are glad that our 100% focus on checkout for Magento pays off: as you say, we make it work. That's what we do, all day since 2010.
Here are some top best magento one step checkout extension
+ Magestore One Step Checkout : http://www.magestore.com/magento-2-one-step-checkout-extension.html/
+ One Step Checkout Extension : https://www.onestepcheckout.com/
+ Fancy Checkout Extension : https://www.fancycheckout.com
Greetings to all!
You can also try the Quick One Page checkout extension for Magento. With this module all information needed for checkout can be filled in on the same page without steps and reloads.
Hope this helps!
Best regards, Alex
If you are using Magento 2, this One Step Checkout can be ideal for you to reduce cart abandonment and increase conversion rates
+ Display all elements for checking out in only 1 page so that customers can complete it easier without experiencing many steps
+ Auto detect customer places and autocomplete customer addresses by Google Suggest when they just type some letters
+ Auto update information when related ones change: update order review when shipping methods change, update shipping methods when shipping addresses change and update billing addresses when shipping addresses change
+ Allow customers to choose their dates and times to receive orders and also leave comments
+ Support multiple payment methods
+ Add more options to the checkout page such as discount code, gift message and newsletter subscription
+ Show delivery date and delivery comment information in the order detail
For Magento 2 sites, we also can reduce checkout steps to 1 step only by displaying all information in 1 page only with the help of Magento 2 One Step Checkout Extension
You may check webkul one step checkout extension for Magento 2 - https://store.webkul.com/One-Step-Checkout-Magento2.html