Firsty, Codeine is an opiate (a naturally occurring alkaloid that is derived from the opium poppy).
Tramadol is an opioid (a synthetic alkaloid created to mimic the action of a natural opiate).
Many individuals will have a wide range of opinions on which creates a better high. This is individual to yourself and personal preference is paramount. There is no set in stone answer. It depends on you!
Having abused both of these drugs and forming an addiction to them, I feel that I am adequately experienced enough to offer you my differential opinions.
Tramadol and Codeine are relatives, but their mechanism of action, binding affinities and metabolic properties differ rather substantially. Tramadol possesses the ability to act as a reuptake inhibitor of serotonin and norepinephrine (SNRI), albeit, not particularly strong, but it is present. Simply, this means that Tramadol will induce positive feelings,thus generating varying degrees of mood elevating and stimulatory effects. Euphoria presents in some users, this is debatable, as some individuals lack the enzyme CYP2D6 (the same as Codeine), which is responsible for metabolising Tram into O-desmethyltramadol, Generally speaking, Tramadol is a rather chaotic and 'dirty' high, IMHO. As I am sure that you are aware, caution should be ahered to regarding using Tramadol. The seizure risk is very real and abuse/addiction potential may be problematic (been there, very nasty).
Now then, Codeine. I myself prefer this. Albeit, a mild opiate, it is natural, bestows a genuine warmth and glow upon me and makes me feel extremely relaxed. It actually gives me euphoria that Tramadol never could quite reach. The beauty of Codeine for me, is that it is freely available in various over the counter formulations. Granted, you would have to make the effort in performing a CWE if the OTC product contained Caffeine/APAP/Ibuprofen/Aspirin or other nasties. As with Tramadol, the possibility of missing enzyme CYP2D6 (for converting Codeine to Morphine), could hinder effects.
Again, I will reiterate that caution should be at the forefront of your mind whilst using this class of drugs. The addiction risk for Codeine is potentially higher than that of Tramadol. Side effects to be mindful of are; constipation, itchiness, nausea and in severe cases, respiratory depression. Never combine Tramadol and Codeine, or any other opiate/opioid CNS depressants. Avoid that!
A good starting dose, for a naive user, would be 60-120mg, but as always, test the waters slowly. There is potential that you could be allergic to Codeine. Gauge your sweet spot. Continued or daily use of Codeine (or Tramadol) is not advised as this leads to tolerance issues and you could very easily become dependant/chase the high and increase dose, which could result in OD. I have been to the depths of hell with my opiate/opioid addiction and abuse, I beat that, but it isn't a road you want to be going down.
Stay safe.