Hi QDa is a detector which can give you M/Z values,its not a complete mass spec. its is positioned for chromatographers for orthogonality. there is no competition. its not that you can use.It should not be compared with Tradiyional SQD

Secondly LCMSD should be compared with SQD as a single quad.

Thanks for the comment. I was asking for a 'hands-on' opinion because both systems are within comparable price ranges.

Your request is unrealistic. Do not select an LC/MS based on price alone until you understand which system would be a better fit for you (not someone else). The answer will depend on your actual uses, specific application(s), local support needs, training and technical knowledge in their use. Anyone who suggests one over the other without any information regarding the details of your planned needs and applications should be ignored. No credible answer is possible without first spending a great deal of time finding out what your actual needs and training levels are. Please contact a local expert or consultant to sit down with you and review these.

William Letter, absolutely true, but overinterpreted. Did I write anywhere I am willing to pick one basing on solely on someone elses opinion? Multiple factors are to be considerd, 'local experts' available for me would be sales representatives. Well, I talked to them as well. Budget is an important factor so this is not a trivial decission. My needs are: small molecules medicinal chemistry (up to 10 people), small peptide chemistry (might be over 1250 Da). Higher sensitivity might be needed for target-guided drug discovery approaches, but I would not sacrifice robustness and reliability for that. We are not experts in LC/MS instrumentation, in terms of hardware managements and fixing stuff. Personally, I could not find a person in a reasonable km range that uses Agilent LC/MSD. I know Waters has a branch in my country, Agilent do not.

Maciej, not "overinterpreted" at all as I have been providing professional scientific consulting advice in this field for almost three decades. You failed to initially provide any information regarding your applications or needs. You asked for an opinion and you received it. As such, it would be unwise to offer any recommendations without more info. You have provided more applicable and relevant info in your followup response. However, if you have no local support for one of the two proposed instruments (Agilent, which would have the better front end HPLC system and also be easier to service) and you are new to this area, then you may want to skip the Agilent system for now and invest some time in setting up an intial on-site demo at the Waters instrument vendor's facility. This will allow you to bring examples of YOUR proposed samples and pre-developed LC/MS methods for testing on a system which is similar to the one which is of interest to you. These visits are well worth investing money in now, before you purchase. You will also be able to watch more experienced users (Their application chemists and Instrument engineers) use the system and let you operate it so you can get a feel for what it can and can not do. Both the hardware and software should be evaluated and I recommend you take a few days to do this (provided that the instrument vendor will be generous enough to provide you with instrument time to do so). Be sure to bring one or two other people with you for this visit (and they should be end-users of the system, and/or someone with experience). When complete, review the opinions and info gathered. With perhaps exception to local support reviews, "Other" users opinions really do not matter in these cases. *This approach is really the best way to answer these types of question.

William, thanks for your comment!