It depends on whether you play solo or in a combo. If you are in a band with a bass player, they are not going to be happy with you mucking around down in the low registers - that's their land, partner, get yerself back to the mids and fight the guitars there.
As a solo player, you are likely playing jazz or lounge on a shortened keyboard so ideals would something that aligns with the tonic of the more popular piano key signatures. E is not one of those, and neither is A, unless you are a profound lover of Bb (which I am) and want that black key to be your lowest. You are probably better off with C or even F.
Actually the "characteristics" of musical keys is an interesting area. Musical keys resonate at different frequences and some would argue that different emotions are more readily stirred by a particular key. The classical composers were aware of this and used them accordingly. A lot of this can fast descend into astrology-like hooey but it's still worth a bar argument or two:
https://www.wmich.edu/mus-theo/courses/keys.html