It depends on what the application is; how much access you have to the fasteners you are trying to remove. As with all specialty tools; chrome and impact both have their unique uses, characteristics, benefits.
Chrome: typically, articulate at a wider range and angle then impact, are thinner, but usually are more "floppy" then the equivalent impact versions. Many times; just like 1/4" universal sockets; they aren't stiff enough and many people add tape to make them stiffer. These can be the only thing that will work in special; unique and super tight engine compartment situations.... now becoming all to common on newer modern cars.
Impacts: Are stronger (handle air impacts, more abuse), stiffer flexing at the universal joint but don't have the articulation, angle range as the chrome's!
Bottom line: both serve their purpose but neither can do everything the other can do! Access and durability are the primary problem; being able to use a air tool without breaking or prematurely wearing out the universal joint being another issue. If you are working flat rate and see the use of a 1/4" impact or even a 1/4" air ratchet; I would recommend you getting a 1/4" impact set, I noticed my 1/4" sockets were getting deformed even by the use of the air ratchet!
I have a Grey tool 1/4" impact set; which is pretty reasonable and provides allot of 1/4" impact sockets for the money! Metric/Standard: short, deep, swivel, extensions, adapters, etc.
Grey Pneumatic 9771 1/4 Surface Drive 71 Piece Complete
https://www.google.com/search?q=Gre...44,d.aWM&fp=dfd1b788fe5f0707&biw=1280&bih=899
just the universals by themselves:
Grey Pneumatic 9706U
https://www.google.com/search?q=Gre...44,d.aWM&fp=dfd1b788fe5f0707&biw=1280&bih=899
"Grey Pneumatic 71 Pc 1/4"" Surface Drive Master Set (9771) "
https://www.google.com/search?q=Gre...44,d.aWM&fp=dfd1b788fe5f0707&biw=1280&bih=899
Also, check out Sunex, KD, etc.