Lambda ZAP as a vector for bacterial libraries

[billing at vetsci.microvet.arizona.edu]

Before posting this I had a quick look in the archives and although the 
question has been asked before, there weren't a lot of specific replies.

My question therefore is, would people recommend the use of Lambda ZAP 
(Stratagene) (or the derivatives Lambda ZAP II, Lambda ZAP Express, etc) 
for cloning bacterial (not cDNA) libraries.  I would like to make 
several "immortalized" libraries for future use.  The boss wants to try 
cosmids :-( while I would prefer straight lambda.  I thought Lambda ZAP 
might be a compromise (although an expensive one, I know).

Which, if any of the derivatives, is better?  We would screen for clones 
using various combinations of antibody, DNA probes, direct measurement 
of expressed products on plates, etc..

Also, I noticed that there were a few comments in the archives on 
difficulties with "ZAPPING" the bluescript out of the lambda.  Is this a 
general problem, or related to the type of insert in the clone?

Finally, does anyone know of any other similar systems.

TIA

Stephen