Is the BeoSound 4 only really suitable for the likes of BL6000, BL4, BL8000 etc? Or can this player be successfully used with BeoLab 5 without a deterioration in sound ability? 

I think it is fine - though it does not have a digital out. Seems to be similar to the BS3000/3200 in concept and performance.

I noticed it doesn't have digital out, but i'm curious if i will miss out on better sound without a digital connection. I'm suspecting (and hoping) that the innards of the BeoSound 4 are the same as the BeoCentre 2? 

Actually I thought the BeoSound 4 was a step ahead of the 3200 in terms of radio performance. Can't say I've noticed much difference with CD, as you say, only demonstrated with BeoLab 4s which are pretty hopeless in terms of a 'decent hifi demonstration'. When I compared the BS4 vs BS3200, it was BeoLab 4000s vs BeoLab 3s being driven, but with the BS4, the sound was actually more detailed, which isn't what you'd expect considering the BeoLab 3s were connected to the 3200...

I have heard the BS4 connected to a pair of BL8000, and the sound was very detailed and clear. I would though say, that the BS4 is a big step behind BC2 and BS9000, due to the missing digital output. If I wanted to drive a pair of BL5 or BL9, I would not choose the BS4, because I think you could enjoy your speakers a lot more with BC2 or BL9000.

I would agree with you, but if you only use the PowerLink outputs, I reckon the BeoSound 4 will give better performance...

I love the BS4, but i want to know for sure what the difference is between the digital connection and the powerlink connection. It isn't something you can just guess, and a salesman isn't really going to give me a straight answer as they still work for commission.

tom:

I have heard the BS4 connected to a pair of BL8000, and the sound was very detailed and clear. I would though say, that the BS4 is a big step behind BC2 and BS9000, due to the missing digital output. If I wanted to drive a pair of BL5 or BL9, I would not choose the BS4, because I think you could enjoy your speakers a lot more with BC2 or BL9000.

But the BL9s don't have a digital input. The display in the BS4 is the same as the BC2. There is of course the new Audio BC2 - tricky to see what it offers over the BS4 except the digital out.

Peter:

But the BL9s don't have a digital input. The display in the BS4 is the same as the BC2. There is of course the new Audio BC2 - tricky to see what it offers over the BS4 except the digital out.

Peter:

But the BL9s don't have a digital input...

should have known that. was discussed here.