Lyme disease, while more treatable than MS, can actually cause more symptoms. That is because MS affects the CNS, while Lyme can attack juts about any system/part of the body.
For example, many people (but not all) with Lyme will have some form of joint pain, while joint pain is not a primary symptom of MS. Also, while Lyme may cause brain lesions, it does not always do so. I don't know an exact statistic but I think it is more often than not that Lyme patients have clear MRI's, even if they have profound neuro symptoms.
Another difference is response to steroids. MS is autoimmune in nature, so attacks may be treated by steroids that suppress the immune system. Lyme is an infection, so suppressing the immune system is about the last thing that you want to do! People who have undiagnosed Lyme and get treated with steroids often go on to develop more severe and difficult to treat cases of Lyme.
One reason why it is so difficult to tell Lyme apart from other diseases is that actually a lot of Lyme patients have more than just Lyme. Ticks carry other diseases, often referred to as co-infections. Depending on what tick bit you, you can have a very different presentation from someone bit by another tick. Different people may respond differently to the infections as well.
If you're interested more in Lyme, and how it is NOT "difficult to catch, easy to diagnose, and fast to cure," then consider watching "Under Our Skin," a documentary that is available through Netflix and other stream sites, or check out the book "Cure Unknown" by Pam Weintraub.
Or feel free to stop by the Lyme forum.
Best of luck in getting a diagnosis and treatment.
http://www.medhelp.org/forums/Lyme-Disease/show/148