Reglazing a tub is cheapest method. When it is done correctly and also maintain properly, it can last upto 20 years. You can not use a suction cup type bathmat after your tub is reglazed, however a reputable refinishing company will sell you a commerical grade non-slip mat for arount $40 - $60. Do remember, reglazing result can vary greatly by materials, experience, and equipment. So do shop around first. Reglazing will give you a very satifactory "Like new" result. However in most cases it will not be 100% perfect.
In conclusion, if you are looking for a cheap method to renew your old tub and are lot looking for perfection, choose reglaze. If you have more money to spare, looking for perfection and want a real "Brand New" tub that can last for 30-40years, ofcourse Tubliner is the way to go. Additionally, with Tubliner you will get a factory non-slip surface and new drain and overflow with no extra cost from most retailer.
If anyone have any questions regards to reglaze or bathliner. Please visit my company website: www.surfacerx.com, here you can find out pricing, comparison, faq and lots more... Hope this had help you in answering your questions.