Bit late, but, ehh...

This type of information is always hard to qualify, but I'll provide some contextual detail and a few examples of Irish and French musicians' socio-economic status (although can probably discuss more regions if you want).
Throughout the ages, employed/freelance musicians have been celebrated and employed differently. Unfortunately, as with much history, most evidence concerning Medieval musicians is about musicians in Royal/religious settings. Sources of information about these "minstrels" include university statutes, city statutes, tax records, property listings, and private contracts.

In the 11th century, the idea of "minstrelsy" was at risk of becoming too flooded with wandering, idle minstrels to the extent that laws were passed to control the number and movement of them. As the European economy improved, and larger towns began to develop in the 12th century, musicians organised themselves into fraternities and organisations in order to achieve an amount of social status and legal protection. (as was the case with other professions at the time). They would ensure wage guidelines, rights to public performances, geographical jurisdictions, professional ethics, and relief for families of deceased workers. The earliest example being in Arras, in northern France.

From what I gather it seems that their social status improved with the formation of "unions" into a legitimate profession, yet largely one on par or slightly higher than a manual artisan. But this is quite an assumption considering musicians' work could range from street performances, playing in inns, bath houses etc., performing for parades, religious ceremonies, and in royal courts.

• France: City governments became an important source of employment for musicians in 15th century France. A large city band for example, of a handful of wind players and a couple of brass, were annual positions that could be secured for 20/30 years and passed down through generations. A smaller town might employ a trumpeter every now and then. Civic employment offered musicians only portion of a full-time income. Official trumpeters would make an income comparable to candle-makers and cobblers. Other income included charitable fraternities, and religious celebrations, parades, weddings etc. Many musicians also supplemented their income with teaching, and, a surprising amount with property - leasing rural and city property to tenants.

What does this mean? Well, there was a lot of variance in socio-economic status of minstrels. Traditionally people have assumed that they held a social status lower than serfs ... Travelling minstrels, maybe. But permanent residents of a given city (about which more information could be gathered) generally belong in the middle to lower class bracket. The majority of musicians in 15th century France could be considered perhaps on par with labourers, servants, or civic employees such as messengers and squires. The wealthier musicians, more like butchers, fishmongers, retailers, and notaries, grocers and barley merchants.

• Ireland:
  (Bear in mind that this is only the circumstances of an indivual position in the King's court, and not reflective of all musicians, but it does give you an idea of the social status a musician could attain). In Medieval Gaelic courts, the "rig" (or king), would customarily employ an official "filid" (poet) who would write poetry praising the king, but also act as "brithem" (judge). This individual was the highest in position besides the king. Now, the filid would require an "oirfidech" (or musician) in order to perform these poems. The oirfidech was normally a lyre or harp player and they enjoyed a professional status. His legal status was the highest attainable status for a commoner/freeman.

  Primary sources of the time determined that the honour-price (fine levied upon any one who insulted or injured this musician) was "four cows in addition to other payment". It has been suggested that there were two main instruments of the time (among others, of course): a harp-like instrument called a "Cruit" and a plucked lyre called a "timpan". The Cruit player enjoyed more prestige.

Other primary sources, in this case, a seating arrangement and the type of meat served to dinner guests, has the Cuit player seated between judges and horsemen, being served pig shoulders. As are master wrights, and "fifth-grade" poets, and deer-stalkers. Horn and trumpet players are at the next table, near the builders, wrights, and engravers - on par with cooks in terms of status. Pipers are seated next to schoolteachers, soothsayers and druids. Only the cruit players were freeman, but all musicians ranked higher than (in order of prestige): jesters, conjurors, king's fools, satirists, and cordwainers.

Sources:

• Buckley, A. (200): Music and Musicians in Medieval Irish Society. Early Music. Vol. 28, No. 2, Early Music of Ireland (May, 2000), pp. 165-190.

• Peters, G. (2000) Urban Ministrels in Late Medieval Southern France: Opportunities, Status and Professional Relationships. Early Music History. Vol. 19 (2000), pp. 201-235.

• Slocum, K. B. (1995): 'Confrérie, Bruderschaft' and Guild: The Formation of Musicians' Fraternal Organisations in Thirteenth- and Fourteenth-Century Europe. Early Music History. Vol. 14 (1995), pp. 257-274.