Enlarging lenses often make good macro lenses, sometimes reversed, but it's best to test the lenses you actually have in hand. Be aware that the cost of the lens is not necessarily indicative of how well it will perform in a use it's not designed for. For instance, I once tested three Canon FD 50mm lenses reversed for macro--the 1.8, 1.4, and 1.2L, and no question, in that use, the cheap 1.8 outperformed the 1.4, and the 1.4 did better than the 1.2L. Some lenses that are otherwise good might have surprising problems when reversed or used for macro, like excessive flare or vignetting or barrel distortion.
Generally, I've found that my dedicated macro lenses work better than my particular enlarging lenses, and for some reproduction ratios, some of the latest non-macro lenses happen to be very well corrected in the macro range. For instance, I've used both my Zeiss 35/2 ZS and Canon 45/2.8 TS-E for copying negs, transparencies, and contact prints in the medium and large format ranges on my 5DII, and they're both up to the task.
The Tamron SP 90/2.5 Macro, which is outstanding on film and with small-sensor digital cameras, I've found, produces flare on my 5DII, I presume due to reflections between the full-frame sensor and the rear element of the lens.
For 35mm negs and transparencies, I use the Canon FD 35/2.8 Macrophoto, which is an RMS mount lens. To get a full frame copy on the 5DII, I use it on an RMS-M42 adapter with an M42-EOS adapter. The original RMS-FD + FD-EOS macro adapter gives a few mm more extension, and then I have a collection of extension tubes to get higher magnification, if I need. For instance, if I want a 50 megapixel scan or a crop from a 35mm original, I can use extension tubes to shoot 9 overlapping panels and stitch them in Photoshop.