If glycolic acid worked for you, I see no reason to stop using it. Salicylic acid is even better for acne and blackheads-prone skin because it has a comedolyitic (de-clogging) effect. It penetrates the pores and disrupts the sebum that plugs them. There is a popular myth that blackheads consist of dirt and they are caused by poor hygiene. Blackheads are in fact a mixture of sebum (oily substance produced by sebaceous glands inside the pore) and keratin (a tough, protective protein in the outer layer of the skin). The dark color of blackheads is due to accumulated melanin pigment deposition. Melanin is a pigment normally present in the skin, making up our skin color. The blackheads are only pigmented at the tip.
To get rid of blackheads, you have to soften the keratin-sebum mixture. It is not an easy task. Keratin is very strong and tough material. In combination with oily sebum, it basically forms "glue" that plugs the pore. Keratolytics are substances that soften keratin. Salicylic acid is a keratolytic. Prolonged exposure to warm water also softens keratin however, oily sebum repulses water, and moreover you cannot dissolve the plugs with water or soap.
Salicylic acid is oil-soluble (contrary to glycolic acid and other Alpha Hydroxy Acids) and therefore can penetrate the oily pore and soften the plug. Prolonged contact with the skin is needed. Cleaning the skin with a product containing salicylic acid is good but not enough. Every now and then, you have to apply a higher percentage of salicylic acid, massage it into the pores and leave it on the skin for an hour or longer.
Furthermore, it has anti-inflammatory and anti-microbial properties, making it ideal for acne control.
To make a long story short, I think you will be much better off with salicylic acid than microdermabrasion.
The plugs can also be softened by prolonged contact with oils:
https://http://forums.owndoc.com/dermarolling-microneedling/Oil-cleansing-method-to-get-rid-of-blackheads