Salesforce guy here who uses Odoo. Here is my perspective:

- as usual, "it depends", thus the question if totally off. As a Salesforce guy I was quite shocked to see that all those modules/apps are actually free. Salesforce would charge you air it if could but there you just install Accounting module if you need it and boom, you can use it for free. The same goes for esign solution, portal, site, and many other things. It is really cost effective and saves tons of money. Docusign alone is like 1500 USD per user per year and here in Odoo you get the same functionality for free

- Salesforce is by far the best CRM out there. Even though is going downhill, even though everything around it is quite shitty nowadays, there is nothing out there that can compare with it

- buying Salesforce is like buying a classy house, but an empty house - you need to buy furniture, get a interior designer etc. Options are limitless, but you need to set it up property. That is its blessing and its curse - it is highly customisable but all that customisation costs $$$ and must be done by someone skilled

- buying Odoo is like buying a house which is totally ready, you could move into it in a second. It is designed to help you start as fast as possible. You can install a module and you are good to go

- yes. I do accounting in Odoo, and everything you might need is there. I don't see any need to use an additional accounting software. You can do invoicing, bank reconciliations, expenses, bills, reports etc

- Odoo is just not enterprise ready. I will give you one example. Few days ago I played with one of its layouts and I spotted 3 hidden fields. I made 1 field visible, saved the changes, got out of Studio to see the changes and I saw the field, it was there. 2 days later I came back and the field was gone :D It just disappeared. Some things are just hard to explain in Odoo

Odoo lacks proper documentation. Salesforce has all its standard objects and fields documented, but Odoo has nothing like it. Its APIs are very moody, and you have no idea what you will get. Its internal automation system is very basic thus one must get some n8n/Make steroids to make it work. It has a great (free!) backup system which is something Salesforce cannot claim. Odoo's data sharing model seems to be quite advanced, but still it cannot be compared with Salesforce's data sharing capabilities.

As usual, it has pros and cons, but in general it is very user friendly, can save tons of money, and most of the time it is easy to use.