Which is better for everyday wear?

The Lace Bra and Panty Set. Full coverage, a hipster brief and gentle machine wash make it the more practical everyday pick. The BKKKB set is a halter plunge with a thong, built for occasions.

Which gives more support?

The Lace set. Its thick-under-thin molded cups shape and support without a wire. The BKKKB bra is unpadded and wireless, so it holds shape loosely.

Which is better under a low-cut top?

The BKKKB halter set. The plunge halter follows a low neckline and ties the look to the shoulders. The Lace set's full coverage can peek out.

Is the Lace set worth stepping up to?

Yes if you want coverage, adjustable straps and easier care. Skip it if you want a plunge halter or a thong; the BKKKB set covers those.

The Lace set likely does. Gentle machine wash is allowed and the molded cups hold shape. The BKKKB set needs hand washing and its thin lace and elastane stretch wear faster.

Do either have underwires?

No. Both are wire-free. The Lace set uses molded cups for shaping; the BKKKB set relies on the halter neckline alone.

Halter Bra and Panty Lace Lingerie Set vs Lace Bra and Panty Set

Buy the BKKKB halter set for a romantic occasion or a plunge, halter-neck look; buy the Lace Bra and Panty Set for all-day wear and fuller coverage. The BKKKB set is a thin, unpadded, wireless halter with a thong, so it is more decorative than supportive. The Lace set is a full-coverage, non-padded, wire-free bra with a mid-waist hipster and molded cups, and its 4.7 rating from 719 ratings points to steady owner satisfaction.

Choose the BKKKB halter set if you want a plunge, halter-neck look with a thong for a date night, anniversary or bridal moment.
Choose the Lace Bra and Panty Set if you want full coverage, a hipster brief and a wire-free bra you can wear all day.

Prices

Halter Bra and Panty Lace Lingerie Set: $9.99 at Amazon (checked today)
Lace Bra and Panty Set: $9.99 at Amazon (checked today)
Difference: both cost the same today