Is it advisable to have an all tube system?

Depends on the equipment. Cheap tube equipment will sound..well...cheap. Good tube stuff will sound natural. System synergy, of course, has a lot to do with it. Use tube gear that does not use a lot of tubes and that helps with maintenance cost. For example, avoid preamps that have a bunch of tubes; why would any more than 4 tubes (2 would be better perhaps) for a phono stage and 4 for the linestage? One triode tube can be used for a linestage and a pair for a phono stage. Some phono stages (think Hagerman Trumpet) have as many as TEN tubes just for the phono stage. Same thing with amps; get amps that use easily obtainable tubes and shy away from rare NOS tubes (WE 274B, Mullard GZ34, Telefunken 6922, that sort of thing). Stick with modestly priced tubes with good life such as 300b, 2a3, el84. More powerful tubes such as the 211 and 845 can cost a grand for a pair of true quality NOS.