It was definitely not as bad as Transformers 2, but wasn't great either. This movie doesn't warrant repeat viewings, but it would at the very least make a pretty good reference disc.
Terminator Salvation is only $6.25 on Deep Discount right now for those willing to wait for them to come back into stock. http://www.deepdiscount.com/index.cfm/fuseaction/product.detail/productID/891312E1-7866-47E0-BE70-42B1E25920E1/
It doesn't say so on the Amazon product page, but I could've sworn I read somewhere that there'd be some extra features on the Blu-ray not released on the DVD. I could be mistaken.