I have a bb30 frame, and I need to change my crankset. However, I am baffled by the reviews online if it is better to get a native BB30 crankset, like SRAM Force 22, or an adapted Shimano Ultegra 5800 with the wheels mfg adapter, which I slightly prefer. Would there be any performance or durability losses choosing the adapting way?
If the frame is made for BB30 I'd recommend using that.
Advantages of using native BB:
BB30 spindle is thicker (30mm) and stronger than a gxp (24mm)
No extraneous parts
Advantages of using adapter:
Ease of service - no bearing press needed except for initial install, after which you will have a threaded BB that's easy to remove. BB30 requires relatively expensive tools to service, e.g. Park Tool bearing press and puller, which most enthusiasts don't own. Also, the fact that you only need to service a BB30 once in a while (maybe once or twice a season) makes buying the tools less attractive when one can just take it to the LBS and have them pull your BB30 for relatively cheap.
Q-factor - can be an advantage or disadvantage. Your stance will likely be wider with the adapter. I consider this less desirable but it's all about the fit. I like a narrow stance. You may have knee pain if your q-factor is too narrow or too wide
I would agree with the above poster that if your bike is bb30 thenit would be recommended to stick with a bb30 crank.
However, conversion between bb30 and gxp seems quite popular these days and you would not be alone if you go down that route. If you go through with getting the ultegra crank you might also look at praxis bottom brackets. More expensive, but they may be on to something.
The Wheels adapters and similar are cheap and simple, but they add another mechanical interface for things to go wrong with and leave you with all the downside of BB30 (creak-prone frame interface and questionably durable bearings). Most of the upside of going with a 24mm crank in the first place is avoiding those problems. They do have their place, but mostly that place is someone who has an existing crank they want to make work cheaply and easily, or a race team that needs to quickly build up a whole bunch of BB30 bikes with a sponsor's 24mm cranks.
The Praxis conversion BBs have a very good reputation, and the FSA press-in threaded adapter also seems to work well when properly installed (ie generously Loctited in place).