We aren't afraid to say that we've seen and tested our fair share of aluminum iPhone 4 bumper cases here on Gadgetmac. There's something about the solid CNC machined, cold metal feeling a lot of you love about these bumpers that make some drop considerable amounts of cash on these just for the luxurious good looks some of these aluminum bumpers have to offer. With growing amounts of options and very little time to waste searching for that perfect aluminum bumper for your already ridiculously well engineered iPhone 4 (some say otherwise), we've put together a guide with out top 5 best aluminum bumper cases out there that we think are worth your attention and possibly even your hard earned cash.

Curious as to what out top 5 best choices are? Well, you can jump past that break to see for yourself! It's not hard, click the button below... You can do it!

First on the list in no particular order is the Graft Concepts Leverage. While it can't be entirely called an aluminum bumper, we simply could not leave it out of this guide because it just rocked our socks off. The Leverage is a slim hybrid bumper case compatible with both the AT&T and Verizon iPhone 4 and comes with a back plate insert for full protection transformation.

The Leverage sets itself apart from the rest with its unique metal locking mechanism and integrated sleep/wake button. The exterior is coated with a soft-touch, matte black coating for a smooth feel and extra grip. While this might not truly be an aluminum bumper, there's nothing like it out there and we think the extraordinary metal latch is enough to lure in the metal bumper case fanatics.

Graft Concept's Leverage comes in both chrome and matte metal lever finishes and is available in both black and white colors for $59.95.

Up next is the Draco IV by Draco Design. Otherwise known as the Deff Cleave in Japan. One of the first aluminum bumper to re-imagine what iPhone 4 bumper cases can look like, the Draco IV boasts incredible curvatures in one solid piece of aluminum that has been designed and machined with extreme precision to make for one amazing looking aluminum bumper case that might in fact be the best complementing accessory for your iPhone 4 if you happen to own a supercar.

The Draco IV features machined aluminum buttons including a switch for the silent switch for a seamless dedicated button integration showing the extreme amount of detail put into manufacturing this aluminum bumper many love.

The Draco IV is one of the more expensive aluminum bumpers we've reviewed and can be found for $99.99 in multiple different colors.

E13ctron, pronounced Electron, has been the first ever to create a two-tone aluminum bumper for the iPhone 4 and has ever since been the pioneer to aluminum bumpers having more personal characteristics. The E13ctron S4 and S4V offers both AT&T and Verizon iPhone 4 users to pick from a wide variety of colors and different types of aluminum finishes to make up their very own custom colored E13ctron bumper.

The S4 and S4V are amongst one of out all time favorite aluminum bumpers on the market with the latest being E13ctron's hybrid Acetal model for those who cannot sacrifice any signal reception whatsoever yet still enjoy the best of both worlds. The S4 and S4V are priced at $84.99 while the hybrid Acetal version is a bit less costly at $69.99.

Apex Armor, while being the lesser known of the bunch, is certainly worthy of mentioning in our guide. The Apex Armor aluminum bumper is better known for its stealthy appearance and extremely comfortable design and curiously hides its slight contoured edges. We loved the good amount of internal foam padding that has been added to add a level of shock protection. The Apex Armor is a well performing aluminum bumper and a good choice for those who like a more contemporary design without attracting attention.

Apex Armor's aluminum bumper comes in various types of aluminum finishes and colors for $79.99, and it's compatible with both AT&T and Verizon iPhone 4.

Last but in no way the least on the guide, we have the Blade by Tiger Design. The most successful aluminum bumper to ever be made for the iPhone 4, it's no surprise there are so many fakes out there. The Blade packs a mean punch of raw machined aluminum and a mixture of micro serrations for the ultimate hand grip and unique good looks.

Like the Draco IV, the Blade also features dedicated machined aluminum buttons, all except for the silent switch though. Tiger Design is most known for producing CNC machined aluminum fishing parts so we can understand the amount of precision that we found in the Blade bumper.

With that said, it's worth mentioning that the Blade is the lest comfortable to hold out of the bunch. Unless you're sensitive, the Blade is an astonishing piece of engineering with a wide variety of color customization options. The Blade is internally fitted with shock absorbing padding for protection in case your drop your iPhone 4. The Blade is available for $77.