theloonypin, here is a mini-review of Ubercart stock trackers, which might help you with your decision. Note that the following is just my opinion. I would recommend trying them out on a test site, as your needs might be different.

uc_stockstub http://www.ubercart.org/contrib/4792

Pros:
+ Replaces the "add to cart" button with an "out of stock" badge, when the primary SKU is out of stock. This is very handy, as customers will instantly know that product cannot be purchased.
+ If a product has attributes, an out of stock message will appear when a customer selects a sold-out attribute. [The message also blocks purchase of the item]

Cons:
- The out of stock badge is only controlled by the main SKU. If the main SKU is at zero, the badge will appear, even if attributes are in stock. If the main SKU is above zero, the add to cart button will appear, even if no attributes are in stock (although if the customer tries to select a sold-out attribute, the out of stock message will appear). As a result, it best to disable stock tracking of the main SKU when selling a product with multiple attributes.
- When no attributes are in stock, the customer will receive the out of stock message each time they try to add an attribute to the cart. Although this stops them from ordering out of stock goods, it creates a slight usability issue, as the customer may end up trying to add every attribute to the cart before realizing that none of them are in stock.

uc_multi_stock http://www.ubercart.org/contrib/5097
Pros:
+ Displays out of stock message, when consumer tries to purchase a main SKU or an attribute that is out of stock.
+ Unlike uc_stockstub customers can still purchase attributes when the main SKU is at zero.
+ Not dependent on other contributed modules

Cons:
- Unlike uc_stockstub, there is no out of stock badge. Customers have to add the product cart before being told that it is out of stock. This creates a usability issue.
- Like uc_stockstub, there is no message to alert the user when all attributes have sold out. As a result, the customer may end up trying to add every attribute to the cart before realizing that none of them are in stock.

qrios' stock display script http://www.ubercart.org/forum/support/4037/stock_level_product_page
Pros:
+ Allows customers to instantly see which attributes are in stock (The quantity of ‘in stock’ items are displayed as a table). This is user friendly, as the customer doesn’t have to make any interactions to find this information out.

Cons:
- Doesn’t prevent purchase of out of stock products. Although, you can use it in conjunction with one of the above modules.
- Using it in conjunction with one of the above modules is slightly confusing for customers, as the above modules mark a product as out of stock when it is added to a shopping cart. qrios’ script, however, considers products to be out of stock when the order has been completed. Hence, this could create a situation where qrios’s script displays a product as in stock, but one of the above modules display it as out of stock.
- If no attributes are in stock, no table is rendered, which is confusing to the end user

Conclusion
Overall uc_stockstub and uc_multi_stock are more-or-less equal. From a customers’ point of view, uc_stockstub is very slightly better due to its “out of stock” badge. Although in my opinion, this is only a slight improvement, as the badge is controlled by the main SKU only, which creates a usability issue for products with multiple attributes. You can combine either module with qrios' stock display script to partly overcome their shortcomings. On the whole though, both modules would suit the needs of most stores, so you can't go wrong with either.

Notes:
Be sure to disable uc_stockstub and Inventory API (from the modules menu) before installing uc_multi_stock. I failed to do this and my site become inaccessible due to a fatal error message. In the end, I had to restore the site from a backup.