What are the disadvantages of using Microsoft Solver Foundation for CLP? Solver does have some support in the Express/Standard versions, but would imagine that one would need to buy the expensive Gurobi / Knitro add-ons to accomplish anything more than the most basic constraint programming.
Purely considering it's CLP capabilities, how does Solver compare to ECLiPSe?
The main disadvantage is that Microsoft Solver Foundation is discontinued as a standalone product as mentioned here:
ECLiPSe project on the other hand seems to be a much more established project in the area of constraint programming with substantial number of publications. It is also open source, so there is no possibility for a vendor lock-in.
I'd also recommend considering:
Re: model sizes, For Solver Foundation Express (basic 'free' version):
The Standard version has roughly double the capacity, and the Enterprise/Academic versions are 'unlimited' with no real restriction on core/CPU's used.
Re: advantages A huge (IMHO) advantage of Solver Foundation is the object model approach to defining your models. Makes for easy-to-setup models programmatically in C# or to any language to which you have bindings, or you can use AMPL and MPS inputs if you want. There is a also a custom model definition language (OML) which I haven't used, but looks pretty good.
Re: disadvantage You're tied into a proprietary setup, if that matters to you. For a GNU LP, check out GLPK. I've thrown some >20K contraint models at it no problems, and it has a pretty active user group.
From: Installing Solver Foundation