Jared here from the Guru team. Hope you're well! :)
Connex is definitely a great choicel and has lots of positive reviews. There's also Shoplink-QB: https://apps.shopify.com/shoplink-qb which has a 5 star rating and a lower price point. Both definitely worth looking into.
Also worth noting is that we do offer a free QuickBooks app here: https://apps.shopify.com/quickbooks-online. ;
Hope this helps! :)
Jared | @Shopify
We have reviewed and listed some best Quickbooks apps on Shopify. You can take a look around at this list and easily make a comparison then choose the best one that suitable for you. Here is our writing: 14+ Best Shopify Quickbooks online apps for stores
I don't know exactly which app has a desktop version but I think that vendors creating these apps for users who using desktops most of the time so these apps would work on desktop well. We have prepared a list of best Shopify Quickbooks online apps so you can have a look around and find the one that suitable to you,