I have 2 King Keg Top Taps, but recently bought a Hambledon Bard beer sphere (with additional float). Although the beer sphere has a bottom tap, using the float gives you the advantage of a top tap system with the exception of the clearance for the glass. To get round this I simply stand mine on a shelf.
The advantage of the Hambledon Bard is price...£28 vs KKTT @ £40.
Even with the additional float cost of £4 that saved £8 i.e another kit !!
If I was to buy another one I think I would opt for the Hambledon Bard.